To materialize the miniaturization of a switch valve for switching between suction and discharge of a pump.

In the switch valve, a suction port to a diaphragm pump, a discharge port from the diaphragm pump and a connection port connected with an external apparatus are disposed on the same circle on the same plane. The valve is made up of a packing formed in a shape of being divided into two chambers so that the other not connected to the connection port and outer air are connected while the connection port and one of the other two are connected to make a sealed space, and of a member which is rotatable around the diaphragm pump and which substantially fix the packing to be biased onto the plane. In the biasing member, rotation is restricted in a fixed amount. The connection port and the suction port are connected at one end of the rotation range through the sealed space. The connection port and the discharge port are connected at the other end of the rotation range through the sealed space.