The invention provides a substrate processing apparatus and an exhaust method therefor. The exhaust method prevents the blocking of a gas exhaust path, caused by charged particles which is in an exhaust gas exhausted through the gas exhaust path from a processing chamber container (chamber) and attached to the inner wall face of the gas exhaust path. The exhaust method is to exhaust the gas in the chamber (50) of the substrate processing apparatus. The substrate processing apparatus includes a processing chamber (50) for accommodating therein a processing target wafer (W); a gas exhaust path (51) through which a gas inside the processing chamber (50) is exhausted; a dry pump (52) and a scrubber (53) for collecting harmful components in the exhausted gas successively provided in the exhaust path (51) in a gas flow direction; and an ionized gas supply pipe (55) connected to the gas exhaust path (51) arranged at upstream of the dry pump (52) for supplying the ionized gas to the flowing exhausted gas, charging the charged particles in the exhausted gas and exhausting particles.