diff --git a/ext/json/lib/json/common.rb b/ext/json/lib/json/common.rb
index 7627761b52..320df2a947 100644
--- a/ext/json/lib/json/common.rb
+++ b/ext/json/lib/json/common.rb
@@ -490,7 +490,7 @@ module JSON
   #   }
   #
   def pretty_generate(obj, opts = nil)
-    return state.generate(obj) if State === opts
+    return opts.generate(obj) if State === opts
 
     options = PRETTY_GENERATE_OPTIONS
 
diff --git a/test/json/json_generator_test.rb b/test/json/json_generator_test.rb
index 55a3065ae5..f869e43fbe 100755
--- a/test/json/json_generator_test.rb
+++ b/test/json/json_generator_test.rb
@@ -122,6 +122,22 @@ class JSONGeneratorTest < Test::Unit::TestCase
     assert_equal '666', pretty_generate(666)
   end
 
+  def test_generate_pretty_custom
+    state = State.new(:space_before => "<psb>", :space => "<ps>", :indent => "<pi>", :object_nl => "\n<po_nl>\n", :array_nl => "<pa_nl>")
+    json = pretty_generate({1=>{}, 2=>['a','b'], 3=>4}, state)
+    assert_equal(<<~'JSON'.chomp, json)
+      {
+      <po_nl>
+      <pi>"1"<psb>:<ps>{},
+      <po_nl>
+      <pi>"2"<psb>:<ps>[<pa_nl><pi><pi>"a",<pa_nl><pi><pi>"b"<pa_nl><pi>],
+      <po_nl>
+      <pi>"3"<psb>:<ps>4
+      <po_nl>
+      }
+    JSON
+  end
+
   def test_generate_custom
     state = State.new(:space_before => " ", :space => "   ", :indent => "<i>", :object_nl => "\n", :array_nl => "<a_nl>")
     json = generate({1=>{2=>3,4=>[5,6]}}, state)