Abstract: A toilet cleansing agent dispenser is composed of a cylindrical housing, an inner cylinder, a receiving body, a bolt rod, a base, a coil spring and a float piece. The bolt rod and the float piece are connected. The cylindrical housing is provided with a connection slide piece for fastening with a locating frame for mounting the dispenser in a toilet water tank. The float piece and the bolt rod are capable of up-and-down displacement in accordance with the water level in the toilet water tank, so as to regulate the flow of the toilet cleansing agent from the receiving body into the toilet water tank. As the water level in the toilet water tank rises to a certain level after the flush, the float piece and the bolt rod are caused to rise to seal off the flow hole of the receiving body so as to terminate the flow of the cleansing agent into the toilet water tank.