To provide a simple blower which can suppress the infiltration of a target gas into a shaft hole and having a small size and cost reduction, a blower comprising a first casing (11) formed with a gas passage (11c) for introducing a high temperature gas and a shaft hole (11e) for communicating therewith, a rotating shaft (14) inserted to be freely rotatable within the shaft hole (11e), an impeller (13) housed within the first casing (11) which integrally rotates with the rotating shaft (14), a motor (15) for driving the rotating shaft (14) from the rear end side, a second casing (12) having an interior space (21) which communicates with the shaft hole (11e) and supporting the rotating shaft (14) via bearing (22A, 22B), and a purge gas introduction means (16) which introduces to the interior space (21), a purge gas having a higher pressure than a pressure of the shaft hole (11e), wherein the inflow of an exhaust gas into the shaft hole (11e) from the gas passage (11c) side of the first casing (11) is suppressed by introducing the purge gas into the interior space (21).