A flow control device (1) is capable of performing accurate flow control over a wide pressure range includes: a housing (10); a diaphragm (35) splitting the housing into a gas chamber side to which gas is introduced and a fluid chamber side through which fluid passes, and being activated by the differential pressure generated between the gas chamber side and the fluid chamber side; and a valve body (31) which operates in integration with the diaphragm (35) to regulate the flow of the fluid introduced to the fluid chamber side (29). The diaphragm (35) includes: a base part (35b) provided in a substantially central part of the diaphragm; and a thin film part (35c) provided on the outer rim of the base part (35b). An opposing surface which is provided on the fluid chamber side to oppose the diaphragm includes a retaining form (40d) which retains the shape of the thin film part (35c) deformed by the differential pressure.
