In a walk behind mower (10), a clutch actuating mechanism (24) and a dog clutch (23) is included in the power transmission path for the driven wheels (13). The dog clutch includes an input end (23a) provided with teeth (231), an output end (23b) provided with teeth (232) configured to selectively mesh with the teeth of the first clutch half, and a spring member (26) interposed between the first clutch half and the second clutch half to normally urge the two clutch halves away from each other. The clutch actuating mechanism is configured to displace the two clutch halves toward each other against a biasing force of the spring member by using a drive force transmitted from the power source to the clutch actuating mechanism.
