This drain plug device (1) is provided with: an operation subject part (344A); a plug lid (24); and a transfer body (TM1) which is provided between the operation subject part (344A) and the plug lid (24) and which transfers displacement of the operation subject part (344A) toward the plug lid (24). The transfer body (TM1) is provided with a shaft part (344B) capable of moving in the shaft direction thereof, and a turning part (342) capable of turning relative to the shaft part (344B). A shaft side contact part (344D) provided to the shaft part (344B) and/or a turning side contact part (342B) provided to the turning part (342) has an inclined surface shape which is inclined with respect to the moving direction of the shaft part (344B), and movement of the operation subject part (344A) causes the shaft side contact part (344D) to press the turning side contact part (342B) so that the shaft motion of the shaft part (344B) is converted to a turning motion to turn the turning part (342). Thus, a motion direction converting part that converts a shaft motion to a turning motion can be realized with a simple structure.