Handle device of work machine

A work machine handle device having a foldable handle (22) is disclosed. As the handle (22) is to be changed from a folded-up state to a use state, the handle (22) is turned about a frame (13) as a turning fulcrum. An actuating protuberance (67) provided integrally to a turning member (66) of a clamp body (64) is pushed by a handle engaging/disengaging part (53) provided to a front end of the handle (22), and the turning member (66) is caused to turn. The handle engaging/disengaging part (53) is held from either side and automatically restrained by a clamp mechanism (62). When the handle (22) is changed from the use state to the folded-up state, a restraining mechanism (72) is operated to release the engagement between the restraining mechanism and a distal end (71) of the turning member (66). The turning member (66) is turned by a return force of a spring (65) provided to the clamp body (64), the handle engaging/disengaging part (53) ceases to be restrained, and the handle (22) can be folded up.