PURPOSE: To suppress a noise, and to prevent a sign for informing a refuse dumping time from being turned on even if a suction port for a clearance is used by providing a ventilation part on a side face of a connecting part so as to lead in the open air and to allow it to flow roughly in parallel to a suction air current for flowing together with dust at the time when it is connected to a hose joint or an extension tube.

CONSTITUTION: A ventilation part 26 is provided on a side face of a connecting part 5 a hose joint or an extension tube 3 of a suction port main body 1 so as to lead in the open air and to allow it to flow roughly in parallel to a suction air current for slowing together with dust at the time when it is connected to the hose joint or the extension tube 3. Accordingly, even if the air quantity is narrowed down at the time when a flat suction port 2 is clogged up by the cleaning face in the course of use, it does not occur that negative pressure rises to a prescribed value or above due to the open air from the ventilation part 26. In such a way, it does not occur that a refuse dumping time is informed erroneously to a user, and also, an increase in noise can be suppressed.