diff --git a/src/mechanize/form.cr b/src/mechanize/form.cr
index f3a8606..a6a85d1 100644
--- a/src/mechanize/form.cr
+++ b/src/mechanize/form.cr
@@ -68,7 +68,7 @@ class Mechanize::Form
   elements_with "checkbox", "checkboxes"
   elements_with "button"
 
-  # Returns all fields of <input type="textarea">
+  # Returns all fields of &lt;input type="textarea"&gt;
   def textareas
     fields.select { |f| f.class == FormContent::Textarea }.map &.as(FormContent::Textarea)
   end
diff --git a/src/mechanize/form/button.cr b/src/mechanize/form/button.cr
index 4a55eda..dab59f5 100644
--- a/src/mechanize/form/button.cr
+++ b/src/mechanize/form/button.cr
@@ -1,5 +1,5 @@
 # This class represents button related html element.
-# <button>, and <input> whose type is button, reset, image, submit.
+# &lt;button&gt;, and &lt;input&gt; whose type is button, reset, image, submit.
 class Mechanize::FormContent::Button < Mechanize::FormContent::Field
   getter form_node : Node | Lexbor::Node
 
diff --git a/src/mechanize/form/check_box.cr b/src/mechanize/form/check_box.cr
index b239cbf..c2f6476 100644
--- a/src/mechanize/form/check_box.cr
+++ b/src/mechanize/form/check_box.cr
@@ -1,4 +1,4 @@
-# This class represents <input type="checkbox">
+# This class represents &lt;input type="checkbox"&gt;
 class Mechanize::FormContent::CheckBox < Mechanize::FormContent::RadioButton
   # set checkbox checked
   def check
diff --git a/src/mechanize/form/field.cr b/src/mechanize/form/field.cr
index f98ffee..62166d9 100644
--- a/src/mechanize/form/field.cr
+++ b/src/mechanize/form/field.cr
@@ -1,4 +1,4 @@
-# This class represents <input> elements in the form.
+# This class represents &lt;input&gt; elements in the form.
 class Mechanize::FormContent::Field
   # returns field's 'value' attribute
   property value : String?
diff --git a/src/mechanize/form/hidden.cr b/src/mechanize/form/hidden.cr
index 59557f6..10e8222 100644
--- a/src/mechanize/form/hidden.cr
+++ b/src/mechanize/form/hidden.cr
@@ -1,3 +1,3 @@
-# This class represents <input type="hidden">
+# This class represents &lt;input type="hidden"&gt;
 class Mechanize::FormContent::Hidden < Mechanize::FormContent::Field
 end
diff --git a/src/mechanize/form/image_button.cr b/src/mechanize/form/image_button.cr
index 583f39d..272633b 100644
--- a/src/mechanize/form/image_button.cr
+++ b/src/mechanize/form/image_button.cr
@@ -1,3 +1,3 @@
-# This class represents <input type="image">
+# This class represents &lt;input type="image"&gt;
 class Mechanize::FormContent::ImageButton < Mechanize::FormContent::Button
 end
diff --git a/src/mechanize/form/multi_select_list.cr b/src/mechanize/form/multi_select_list.cr
index a960c72..781b805 100644
--- a/src/mechanize/form/multi_select_list.cr
+++ b/src/mechanize/form/multi_select_list.cr
@@ -1,6 +1,6 @@
 require "./option"
 
-# This class represents <select multiple>
+# This class represents &lt;select multiple&gt;
 class Mechanize::FormContent::MultiSelectList
   getter node : Lexbor::Node
   getter name : String
diff --git a/src/mechanize/form/option.cr b/src/mechanize/form/option.cr
index ad5d4e5..d7d641f 100644
--- a/src/mechanize/form/option.cr
+++ b/src/mechanize/form/option.cr
@@ -1,3 +1,4 @@
+# This class represents &lt;option&gt; of &lt;select&gt;
 class Mechanize::FormContent::Option
   getter select_list : FormContent::MultiSelectList
   getter node : Lexbor::Node
diff --git a/src/mechanize/form/radio_button.cr b/src/mechanize/form/radio_button.cr
index b37aab5..efb0b48 100644
--- a/src/mechanize/form/radio_button.cr
+++ b/src/mechanize/form/radio_button.cr
@@ -1,4 +1,4 @@
-# This class represents <input type="radio">
+# This class represents &lt;input type="radio"&gt;
 class Mechanize::FormContent::RadioButton < Mechanize::FormContent::Field
   property :checked, :form
 
diff --git a/src/mechanize/form/reset_button.cr b/src/mechanize/form/reset_button.cr
index a5385e7..1905131 100644
--- a/src/mechanize/form/reset_button.cr
+++ b/src/mechanize/form/reset_button.cr
@@ -1,3 +1,3 @@
-# This class represents <input type="reset">
+# This class represents &lt;input type="reset"&gt;
 class Mechanize::FormContent::ResetButton < Mechanize::FormContent::Button
 end
diff --git a/src/mechanize/form/select_list.cr b/src/mechanize/form/select_list.cr
index 4670e08..9ce252d 100644
--- a/src/mechanize/form/select_list.cr
+++ b/src/mechanize/form/select_list.cr
@@ -1,6 +1,6 @@
 require "./multi_select_list"
 
-# This class represents <select> which is not multiple
+# This class represents &lt;select&gt; which is not multiple
 class Mechanize::FormContent::SelectList < Mechanize::FormContent::MultiSelectList
   def initialize(node)
     super node
diff --git a/src/mechanize/form/submit_button.cr b/src/mechanize/form/submit_button.cr
index 90aa146..0a67b97 100644
--- a/src/mechanize/form/submit_button.cr
+++ b/src/mechanize/form/submit_button.cr
@@ -1,3 +1,3 @@
-# This class represents <input type="submit">
+# This class represents &lt;input type="submit"&gt;
 class Mechanize::FormContent::SubmitButton < Mechanize::FormContent::Button
 end
diff --git a/src/mechanize/form/text.cr b/src/mechanize/form/text.cr
index e39fd47..8dffbd1 100644
--- a/src/mechanize/form/text.cr
+++ b/src/mechanize/form/text.cr
@@ -1,3 +1,3 @@
-# This class represents <input type="text">
+# This class represents &lt;input type="text"&gt;
 class Mechanize::FormContent::Text < Mechanize::FormContent::Field
 end
diff --git a/src/mechanize/form/textarea.cr b/src/mechanize/form/textarea.cr
index 39a4094..47b53d8 100644
--- a/src/mechanize/form/textarea.cr
+++ b/src/mechanize/form/textarea.cr
@@ -1,3 +1,3 @@
-# This class represents <input type="textarea">
+# This class represents &lt;input type="textarea"&gt;
 class Mechanize::FormContent::Textarea < Mechanize::FormContent::Field
 end