A fluid coupling transmits power from a drive side to a driven side by utilizing kinetic energy of fluid such as oil. The fluid coupling comprises a pump impeller (4) provided on a drive shaft (1), a turbine impeller (5) provided on a driven shaft (9), a housing (20) fixed to the pump impeller (4) and surrounding the turbine impeller, and a multiple disc clutch provided between a drive shaft side and a driven shaft side. The multiple disc clutch is operated to couple the drive shaft (1) and the driven shaft (9) mechanically so that the drive shaft and the driven shaft are rotated at the same rotational speed. Thus, the fluid coupling can improve a power transmitting efficiency because of no slip between the rotational speed of the drive shaft and the rotational speed of the driven shaft.