To provide an interference evading movement controlling method for a marking device capable of sharply shortening the preparation time of an inverted model based on a hemihedral model.

The X-Y axis coordinate positions of plural representative points on a hemihedral model obtained by a three-dimensional measuring instrument 10 are inputted. The moving locus of the marking device 25 at a composite angle between a certain corresponding point and another corresponding point is operated in each control period based on the X-Y axis coordinates of these representative points. When an operator B depresses a button on an operation remote controller 42, a control part 50 moves the marking device along the moving locus. The operator B pierces a drill hole to be a working mark on a model 5 while using the marking device 25. The operation is repeated and working marks are succesively put on the model.