An inflating/deflating device includes a fan unit disposed inside a main housing. A release valve assembly is connected to a deflating port of the main housing for fluid communication with a first air passage of the fan unit. An inlet valve assembly is connected to an inflating port of the main housing for fluid communication with a second air passage of the fan unit. A control unit is provided to control the release and inlet valve assemblies. The control unit is operable to switch a first or a second actuating position. The control unit actuates the fan unit and the inlet valve assembly to perform an inflating mode in the first actuating position, and actuates the fan unit and the release valve assembly to perform a deflating mode in the second actuating position.