A diaphragm pump includes a driving mechanism and a counting sensor. The driving mechanism includes an arm portion attached to a deformed portion that forms a pump chamber, and a crank that rotates integrally with the rotating shaft of a motor, in which the rotation of the crank is converted into a reciprocal motion to make the arm portion reciprocally move. The counting sensor is configured to use the arm portion as a detection target and alternately switch between a detection state and a non-detection state as the arm portion makes the reciprocal motion. It is therefore possible to provide a diaphragm pump capable of detecting a discharge flow rate using an inexpensive ready-made motor.