It is an object of the invention to improve ease of operation of a portable planer (101). Representative portable planer includes a planer body (107), a planer blade member disposed in the planer body and rotates around its longitudinal axis and a front base (103) connected to the planer body for vertical movement with respect to the planer body. Further, the planer includes a cutting depth adjusting mechanism (131) operated by a user to change the vertical position of the front base (103) with respect to the planer body to adjust the amount of protrusion of the planer blade member from the underside of the front base. The cutting depth adjusting mechanism includes an operating member (133) manually turned, a cam member (135) rotating together with the operating member, and a height changing section that engages the cam member and changes the height of the front base based on an output of the amount of cam lift. The cam member has a cam curve that keeps constant the amount of cam lift per unit angle of rotation which is outputted by the cam member.