To provide a small, lightweight fluid coupling device allowing a driving member and a driven member to make smooth relative rotation when the atmospheric temperature is low and hindering them from relative rotation when the atmospheric temperature is high.

This fluid coupling device is composed of a housing 10 rotating in a single piece with a driving member, a shaft 21 installed rotatably on the housing and rotating in a single piece with a driven member, pump elements 31 and 32 of rotary capacity type to perform pumping operation with relative rotating of the housing 10 with the shaft 21, a communication passage 18 formed in the housing 10 and generating communication of a suction port with a discharge port, a control valve 40 to control the rate of flow of a working oil circulating from the discharge to the suction port via the passage 18, and a thermo-sensitive member 50 to shut the control valve 40 in accordance with a rise of the atmospheric temperature, and thereby the relative rotation of the housing 10 with the shaft 21 is controlled.