Flow rate control valve and flow rate control device

A flow rate control valve that is so configured to comprise a pair of valve members each of which has a seat surface being in contact with each other, to provide an internal flow channel that passes through the inside of at least one of the valve members and that opens toward the seat surfaces and to control a flow rate of a fluid flowing out through the internal flow channel to the outside by adjusting a separation distance between the seat surfaces, wherein

• a restricted flow channel is formed in the internal flow channel so that a differential pressure is generated between an upstream side and a downstream side of the restricted flow channel,
• the restricted flow channel is formed in a fitting member that is another member different from the valve member which has the internal flow channel and that is inserted in its entirety into a section of the internal flow channel that is of a uniform diameter throughout,
• on a side of the fitting member facing the seat surface, the restricted flow channel extends to an end surface of the fitting member without substantial tapering, and
• an axial length of the fitting member, which runs parallel to an insertion direction of the fitting member into the internal flow channel, is longer than a width of the fitting member.