To achieve power saving in a valve device including a flow rate adjustment function and a passage shut-off function.

A valve body 10 is connected through a power transmission mechanism 30 to a motor 20 as a driving source. The power transmission mechanism 30 includes a clutch section 50 and a valve body energizing spring 66. The clutch section uses a solenoid 58 as a driving source, and establishes a power transmittable state between the motor 20 and the valve body 10 when the solenoid 58 is in an excited state, and meanwhile shuts off the power transmission between the motor 20 and the valve body 10 when the solenoid 58 is in an unexcited state. The valve body energizing spring moves the valve body 10 in the direction to close an opening 94, when the solenoid 58 is in the unexcited state toward the output side more than the clutch section 50.