Provided is a diaphragm type actuator which drives an operation rod in an axial direction, including: a diaphragm which is connected to the operation rod; a high pressure chamber which is adjacent to one end side of the diaphragm in the axial direction; a low pressure chamber which is adjacent to the other end side of the diaphragm in the axial direction; and a return spring which is provided in the low pressure chamber and urges the diaphragm toward the high pressure chamber. Since an absorption portion is disposed inside the high pressure chamber, a force acting on the diaphragm is absorbed when the diaphragm moves toward the high pressure chamber and stops therein.