PROBLEM TO BE SOLVED: To provide a flush toilet bowl device which can suppress variation in a water surface of stored washing water by resistance means reducing a flow speed flowing along a water storage tank inner surface, in the case where tank water supply is performed with the washing water having a large flow speed jetted from a jet nozzle.SOLUTION: A flush toilet bowl device which supplies washing water to a toilet bowl body by a jet pump action includes: the toilet bowl body; a water storage tank; and a jet pump unit 32 which is the jet pump unit including a throat pipe 38, a jet nozzle 40, and a switching valve 96 for switching a travelling direction of the washing water jetted from the jet nozzle into an outside direction of the throat pipe from an inside direction of the throat pipe. On the inner surface of the water storage tank, resistance means 130 is provided in which the washing water jetted from the jet nozzle and whose direction is changed to the outside direction of the throat pipe by the sw
