To provide an air pipe type differentia distribution sensor which enable an air pipe to easily and securely be connected to a selector cock.

A selector cock 1 is provided with nozzles PN1 and PN2 for the air pipe and a coupling gasket 10 as a coupling means is provided between the nozzle PN1 and PN2 and air pipe 2. The coupling gasket 10 is equipped with a nozzle connection part which is arranged almost along the nozzle PN1 and PN2 and made of an elastic member, and an air pipe connection part which is arranged crossing the nozzle coupling part almost at right angles and made of an elastic member. One of the nozzle coupling part and nozzle PN1 and PN2 are inserted into the other and elastically held, and the other is inserted into the air pipe connection part and air pipe 2 and elastically held.