Abstract: An apparatus for machining turbine blades of a radial entry type to form in each blade a groove of a Christmas tree shape for mounting the blade on a turbine rotor including a main spindle, a rotary disk supported on the main spindle, and a plurality of cutters supported on the rotary disk through a cutter holder in positions forming an arc on the surface of the disk. The cutters are located such that those of a configuration suitable for use in giving coarse finishes, those of a configurator suitable for giving middling finishes and those of a configuration suitable for giving final fine finishes are arranged successively in positions forming an arc on the disk. A blade to be machined is supported in a position in which a groove thereof crosses paths of movement of the cutters as the disk is rotated. Thus, the blade can be machined to give fine finishes to the groove.