PURPOSE: To provide a power implement advancing with the front side of a footgear repetitively lowered and made horizontal by providing rollers having outer wheels rotated by a one-way clutch only in the advancing direction and connecting a pivotal arm pivoted collapsibly to a footgear member with a link fixed to the shaft of the one-way clutch.

CONSTITUTION: The centers of rollers 7, 9 are rotatably supported by pivotal support members 10, 11 at nearly same level on the lower surface of a footgear member 1. On a pivotal arm having the lower end displaced at the level lower than or nearly same as that of a straight line interconnecting the centers of the rollers 7, 9 is provided a second roller 8 having an outer ring 18 rotated in the advancing direction by a one-way clutch 16 fitting on a shaft 21 of an inner ring 17. Further, the pivotal arm 20 supported collapsibly by the footgear member 1 is connected to a link 22 fixed to the shaft 21 of the one-way clutch 16. The weight loaded on the rear of the footgear member 1 causes the rollers 7, 8, 9 to contact the ground and generates propelling power for advancing the rollers.