diff --git a/ruby/red-arrow-format/lib/arrow-format/array.rb b/ruby/red-arrow-format/lib/arrow-format/array.rb
index 20929493e90..90a3be41ce9 100644
--- a/ruby/red-arrow-format/lib/arrow-format/array.rb
+++ b/ruby/red-arrow-format/lib/arrow-format/array.rb
@@ -16,6 +16,7 @@
 # under the License.
 
 require "bigdecimal"
+require "date"
 
 require_relative "array-builder"
 require_relative "bitmap"
@@ -489,11 +490,12 @@ def type
     end
 
     private
+    UNIX_EPOCH = Date.new(1970, 1, 1).jd
     def pack_value(value, template, type)
       if value.nil?
         [0].pack(template)
       elsif value.is_a?(Date)
-        [value.day].pack(template)
+        [value.jd - UNIX_EPOCH].pack(template)
       else
         [value].pack(template)
       end
diff --git a/ruby/red-arrow-format/test/test-date32-array.rb b/ruby/red-arrow-format/test/test-date32-array.rb
index 331daabd833..2d9a22c4c9b 100644
--- a/ruby/red-arrow-format/test/test-date32-array.rb
+++ b/ruby/red-arrow-format/test/test-date32-array.rb
@@ -35,6 +35,18 @@ def test_mixed
       assert_equal(values,
                    ArrowFormat::Date32Array.new(values).to_a)
     end
+
+    def test_date
+      values = [
+        Date.new(1969, 12, 31),
+        Date.new(1970, 1, 1),
+        nil,
+        Date.new(2025, 12, 9),
+      ]
+      expected = [-1, 0, nil, @date_2025_12_09]
+      assert_equal(expected,
+                   ArrowFormat::Date32Array.new(values).to_a)
+    end
   end
 
   sub_test_case("#==") do