Abstract: There is disclosed a positioning head for cutting and marking apparatus, whereby when a plurality of cutter wheels or marking-off wheels are successively moved into place, the positioning head or heads which have already been positioned in place can be locked in place. The positioning head comprises, within a housing mounted on the boss of the cutter or marking-off wheel and slidably fitted on two guide bars, a feed gear threadedly engaged with a feed screw shaft which is extended through the housing, an input gear slidably mounted on an input shaft which is extended through the housing, a group of driving gears for transmitting the rotation of the input gear to the feed gear, and a clutch for connecting and disconnecting the driving force transmitted to the feed gear from the input gear, whereby after the positioning head has been put in place, the clutch may be disengaged so as to lock the positioning head in place while any other positioning head is being moved.