PURPOSE: To place a fixed quantity of a medicine in and dissolve every time when a toilet bowl is used by allowing the medicine to enter a cavity when a piston is in a high elevation and the medicine in the cavity to be discharged into flushing water.

CONSTITUTION: Flushing water in a water tank 1 is discharged from a discharge pipe 5, thereby lowering a float 16. The movement of the float 15 is transmitted by way of a vertical rod 15 which makes a vertical motion, thereby lifting up a piston 14. At the same time, a cavity of the piston 14 is inserted into a medicine tank 11 where a liquid or sphere-shaped medicine is placed into a cavity 19. Then, flushing water is fed into the water tank 1, thereby lifting up the float 16. The movement of the float 16 is transmitted to the piston 14, thereby lowering the piston 14 where the cavity 19 in the piston 14 is positioned below a cylinder 13. At the same time, a medicine is dropped and dissolved in the water.