To provide a flow rate regulating valve capable of detecting a state where a flow path is fully closed even when there is no lead wire or the like for detecting the state where the flow path is fully closed. A flow rate regulating valve is a fluid regulating valve including a valve body for opening and closing fluid flow paths provided in a body and includes an actuator unit for moving the valve body, and the actuator unit includes a drive motor, a slider moved by a rotation of the motor, a cylindrical body mounted on the slider, and a shaft interlocked with the cylindrical body and provided with the valve body fixed to a distal end thereof. The motor is a stepping servomotor, and has a pressing control function for moving the valve body in the closing direction at a continuous rated torque.