To provide a clutch device capable of accomplishing a power transmission efficiency almost by 100%, and also exhibiting an impact absorbing function in connection with gear change.

In this device provided with an oil container 20 full of oil, and with a power transmission part 30 submerged in the inside of the oil container 20, a power transmitting condition, in which power from a power source side is penetrated through the oil container 20 so as to be transmitted from a driving shaft 41 connected with the power transmission part 30 to a driven shaft 42 which is connected with the power transmission part 30, and is penetrated through the oil container 20, is adjusted in a range from a releasing condition up to a power transmission condition under an almost 100% power transmission rate by means of adjustment to be made for the quantity of inflow oil to the internal mechanism of the power transmission part 30 and the internal parts of the power transmission part 30, and the quantity of outflow oil from the internal parts as well.