Abstract: An apparatus for grooving a tire which comprises a tire support shaft for rotatably supporting the tire and a support frame having a cutter device mounted thereon. The cutter device and the tire support shaft are movable relative to each other in a transverse direction parallel with the tire support shaft and perpendicular to the tire support shaft. The cutter is supportable at a desired angle with the tread surface, and the cutter blade is rotatable in the direction of the groove to be formed. The cutting position of the cutter is on the axis of an arm support shaft and is controllable by the combination of orthogonal coordinates to simplify the control program for the apparatus. When required, the cutter is swingably attached to a cutter holder to enable the cutter to cut the tire rubber and to be released therefrom with ease without the need to heat the cutter.