An inflator with an air guiding sleeve includes a chassis, a core and a drive motor installed in the chassis, an air guiding sleeve and a cooling fan. The air guiding sleeve has an air guiding hole penetrating through the air guiding sleeve. The drive motor includes a main body and a shaft rotatably installed to the main body, and the shaft has an end protruded from the main body and provided for driving the core to move and the other end protruded from the main body and provided for connecting the cooling fan. The air guiding sleeve includes a positioning shell and an air guiding ring connected to the positioning shell, and the positioning shell is installed to the chassis and/or the drive motor, and the air guiding ring is sheathed onto the external side of the cooling fan and installed around the cooling fan.