To perform cutting and grinding machining for a work with high accuracy and with high efficiency.

In a machine tool, a chuck 2 is mounted on a spindle 1, and a Z-axis slide 3 moving in parallel to the direction of the shaft center of the spindle 1 and an X-axis slide 4 moving at right angles to the direction of the shaft center of the spindle 1 are provided. The X-axis slide 4 is provided with devices 31, 32 for fixing a cutting tool (b), bearing a rotating shaft 21 of a grinding wheel (g), and driving the rotating shaft 21 to be rotated. The spindle 1 is driven to rotate, thereby turing a work (w) held on the chuck 2, and one or both of the X-axis slide 4 and the Z-axis slide 3 are moved to move the cutting tool (b) and the grinding wheel (g). First, the cutting tool (b) is brought into contact with the work (w) held on the chuck 2 to cut the rotating work (w), and subsequently the rotating grinding wheel (g) is brought into contact with the work (w) still held on the chuck 2 to grind the rotating work (w).