PURPOSE: To improve the safety of a working vehicle by providing a claw clutch in-between an engine and a traveling friction clutch in a condition of being connected to said traveling friction clutch and stopping power transmission to a traveling device even in a power transmittable condition.

CONSTITUTION: A traveling friction clutch A is engaged while engaging parts 10B, 12A are brought to an engaged condition by the energizing force of a spring 11 to transmit power from a power transmission shaft 5 to an input shaft 6. And, a piston 12 is moved rightward via an oscillation operating member 14 to disengage the traveling friction clutch A while releasing the engagement between engaging parts 10B, 12A, by the stepping operation of a clutch operating pedal 13. Accordingly, even if driven side friction disks 10A are rotated accompanying the rotation of the power transmission shaft 5, the rotation is not transmitted to the input shaft 6, improving the safety of a working vehicle.