A flush toilet includes a bowl part, a drainage water trap part that is connected to a bottom part thereof, and a water drainage socket that is connected thereto and includes a back side R part that changes a flow channel so that washing water flowing from an upper side is directed to a front side, a front side R part that is provided on a downstream side of the back side R part and changes a flow channel so that washing water flowing from a back side is directed to a lower side, a water storage part that stores a part of washing water on a flow channel from the back side R part to the front side R part, and a throttle part that is provided on a downstream side of the front side R part and decreases a cross-sectional area of a flow channel thereof.