To provide a diaphragm type variable aperture device in which a gap between a diaphragm and a valve seat can be set to a predetermined gap without installing a device such as a gap adjusting mechanism, and to provide a method for manufacturing the same.

The diaphragm type variable aperture device has a first housing 11 in which a first opening 21 is formed, the second housing 12 in which a second opening 22 is formed so as face the first opening 21, the first holder 32 formed in the peripheral fringe of the first opening 21, the second holder 33 formed in the peripheral fringe of the second opening 22, the diaphragm 13 which is arranged between the first opening 21 and the second opening 22 and whose fringe is held by the first holder 21 and the second holder 22, a fluid introducing passage 41 communicating with the first opening 21, the valve seat 45 arranged in the first opening 21, a fluid supplying passage discharging fluid according to the gap 43 between the diaphragm 13 and the valve seat 45, the first holder 32 of the first holding 11 and the valve seat 45 are separated, the first holder 32 can be attached to and detached from the valve seat 45.