<p>The large-diameter section (31) of an attaching shaft (3) projecting from a toilet main body (B) is inserted in an attaching hole (22) in a device main body (2). The small-diameter portion (32) and abutment portion (33) of the attaching shaft (3) are projected upward above the attaching hole (22) in the device main body (2). The upper surface (2a) of the device main body (2) is formed with a guide (23) for internally receiving the abutment portion (33). The circular plate (41) of a lock member (4) is rotatably inserted in the guide (23). The lock member (4) is formed with a through hole (43) which allow the small-diameter portion (32) and abutment portion (33) to be inserted therein and removed therefrom when the lock member (4) is rotated to a release position but which do not allow such insertion or removal when the lock member (4) is rotated to a lock position. Formed in the vicinity of the through hole (43) is a flat surface (45b) which positionally fixes the lock member (4) by pressure contact with the lower surface (33a) of the abutment portion (33) when the lock member (4) is rotated to the lock position.</p>
