To make an edge proceed in a correct direction without moving the edge in long moving distance by repeating edge control action at least twice when the edge direction before edge control action is different by a specified angle or more from a reference direction.

An edge angle control soft 58 is stored in a memory 56 of a controller 54. When a head goes to take a cutter pen from a pen stocker 64 and holds the cutter pen, the controller 54 judges whether or not the edge direction of the cutter pen is within a range of 180°± a specified angle to a reference direction, that is, whether the edge direction is retrorse or close to retrorse. In case of the controller 54 judging negative, edge control action is performed once, and in case of judging affirmative, edge control action is performed continuously twice. The relative moving quantity of the edge and a friction face, and the edge direction is positively controlled into the reference direction so as to improve work efficiency.