diff --git a/app/assets/javascripts/diff.js b/app/assets/javascripts/diff.js
index 4ddafff428f..82bfdcea0ca 100644
--- a/app/assets/javascripts/diff.js
+++ b/app/assets/javascripts/diff.js
@@ -43,10 +43,6 @@
             bottom: unfoldBottom,
             offset: offset,
             unfold: unfold,
-            // indent is used to compensate for single space indent to fit
-            // '+' and '-' prepended to diff lines,
-            // see https://gitlab.com/gitlab-org/gitlab-ce/issues/707
-            indent: 1,
             view: file.data('view')
           };
           return $.get(link, params, function(response) {
diff --git a/app/assets/stylesheets/pages/diff.scss b/app/assets/stylesheets/pages/diff.scss
index fde138c874d..99fdea15218 100644
--- a/app/assets/stylesheets/pages/diff.scss
+++ b/app/assets/stylesheets/pages/diff.scss
@@ -92,20 +92,6 @@
 
         &.noteable_line {
           position: relative;
-
-          &.old {
-            &::before {
-              content: '-';
-              position: absolute;
-            }
-          }
-
-          &.new {
-            &::before {
-              content: '+';
-              position: absolute;
-            }
-          }
         }
 
         span {
@@ -151,8 +137,9 @@
     .line_content {
       display: block;
       margin: 0;
-      padding: 0 0.5em;
+      padding: 0 1.5em;
       border: none;
+      position: relative;
 
       &.parallel {
         display: table-cell;
@@ -161,6 +148,22 @@
           word-break: break-all;
         }
       }
+
+      &.old {
+        &::before {
+          content: '-';
+          position: absolute;
+          left: 0.5em;
+        }
+      }
+
+      &.new {
+        &::before {
+          content: '+';
+          position: absolute;
+          left: 0.5em;
+        }
+      }
     }
 
     .text-file.diff-wrap-lines table .line_holder td span {
diff --git a/app/helpers/diff_helper.rb b/app/helpers/diff_helper.rb
index 0725c3f4c56..f489f9aa0d6 100644
--- a/app/helpers/diff_helper.rb
+++ b/app/helpers/diff_helper.rb
@@ -51,12 +51,11 @@ module DiffHelper
     html.html_safe
   end
 
-  def diff_line_content(line, line_type = nil)
+  def diff_line_content(line)
     if line.blank?
-      "  ".html_safe
+      " ".html_safe
     else
-      line[0] = ' ' if %w[new old].include?(line_type)
-      line
+      line.sub(/^[\-+ ]/, '').html_safe
     end
   end
 
diff --git a/app/views/projects/diffs/_line.html.haml b/app/views/projects/diffs/_line.html.haml
index 7042e9f1fc9..a3e4b5b777e 100644
--- a/app/views/projects/diffs/_line.html.haml
+++ b/app/views/projects/diffs/_line.html.haml
@@ -25,9 +25,9 @@
         %a{href: "##{line_code}", data: { linenumber: link_text }}
     %td.line_content.noteable_line{ class: type, data: (diff_view_line_data(line_code, diff_file.position(line), type) unless plain) }<
       - if email
-        %pre= diff_line_content(line.text, type)
+        %pre= diff_line_content(line.text)
       - else
-        = diff_line_content(line.text, type)
+        = diff_line_content(line.text)
 
 - discussions = local_assigns.fetch(:discussions, nil)
 - if discussions && !line.meta?
diff --git a/changelogs/unreleased/remove-heading-space-from-diff-content.yml b/changelogs/unreleased/remove-heading-space-from-diff-content.yml
new file mode 100644
index 00000000000..1ea85784d29
--- /dev/null
+++ b/changelogs/unreleased/remove-heading-space-from-diff-content.yml
@@ -0,0 +1,4 @@
+---
+title: Remove an extra leading space from diff paste data
+merge_request: 7133
+author: Hiroyuki Sato
diff --git a/spec/helpers/diff_helper_spec.rb b/spec/helpers/diff_helper_spec.rb
index 9c7c79f57c6..837e7afa7e8 100644
--- a/spec/helpers/diff_helper_spec.rb
+++ b/spec/helpers/diff_helper_spec.rb
@@ -61,7 +61,7 @@ describe DiffHelper do
 
   describe '#diff_line_content' do
     it 'returns non breaking space when line is empty' do
-      expect(diff_line_content(nil)).to eq(' &nbsp;')
+      expect(diff_line_content(nil)).to eq('&nbsp;')
     end
 
     it 'returns the line itself' do