A parallel-to-serial interface circuit includes an equalizer to delay odd data by a half period and sequentially generate odd pre data, odd main data, and odd post data, and delay even data by a half period and sequentially generate even pre data, even main data, and even post data, a final parallel-to-serial converter to sequentially and alternately select the even pre data and the odd pre data to generate pre data, sequentially and alternately select inverted odd main data and inverted even main data to generate inverted main data, and sequentially and alternately select the even post data and the odd post data to generate post data, and a driver to drive the pre data to generate a pre data level, drive the inverted main data to generate an inverted main data level, and drive the post data to generate a post data level.