A polarizing element includes a substrate with protruded threads, and metal thin wires provided on the protruded threads. Each metal thin wire includes a first thin wire provided to a first side surface of the protruded thread and a second thin wire provided to a second side surface of the protruded thread. Each first thin wire has a first volume. Each second thin wire has a second volume. Each metal thin wire has a third volume which is the sum of the first and second volumes. As a distance from one end of the substrate increases, the volume of each first thin wire decreases and the volume of each second thin wire increases so that the third volume is maintained within a predetermined range.