PURPOSE: To prevent bad odor from circulating to rooms and at the same time attempt energy saving by operating deodorizing device only during the toilet is being used and for a certain time after the use of the toilet and making the air discharge from the toilet only through a deodorizing device.

CONSTITUTION: When a toilet user turns ON electric power to a delay timer switch 30 before he uses a toilet, the fan motor 23 of a deodorizing device 26 starts to rotate, and the dirty air and bad odors such as the smell of human waste, etc. are deodorized by the deodorizing filter 24 in a deodorizing device 26 and the discharge air is led as clean air to an indoor air discharge duct 17. On the other hand, the damper 28 of an electrically operated damper 29 rotates by 90° and stops so as to close an air channel 31. When a toilet user makes a delay timer switch 30 start after using the toilet, the deodorizing device 26 stops and the damper 28 opens, that is, the air passage 31 becomes open and the air in the toilet (at this time the air in the toilet has been deodorized) is discharged from a suction port 18.