An automatic depressurizing pump includes an air-generating unit and an airflow control unit. The air-generating unit has a first air intake hole. An air generated by the air-generating unit drives the air control unit so as to inhale or exhale airflows through the first air intake hole. The airflow control unit includes a valve base, a first valve, a second valve, a top cover, and a resilient member. The valve base includes an air output chamber and a pressure chamber. The resilient member includes a second air output hole and a depressurization valve. The second air output hole is communicated with the top of the air output chamber, and the depressurization valve hermetically covers on and fixes to the top of the pressure chamber.