An inflation device includes an airbag and an air valve. An air inlet is provided at an upper end of the air valve, an air outlet is provide at a lower end of the air valve, an inlet valve that is unidirectionally opened. inwards the air valve is provided at the air inlet, the inlet valve can be opened to a deflation position, an outlet valve is provided at the air outlet that is unidirectionally opened outwards the air valve, a push aim extending towards the outlet valve is configured in the air valve and is movable up and down, the push arm is actuated to move towards the outlet valve if the inlet valve is opened, and is pressed against the outlet valve if the inlet valve is at the deflation position. The deflation operation of the inflation device is simple due to the configuration of the push arm.