PROBLEM TO BE SOLVED: To provide an automatic lathe to execute simultaneous machining of different kinds by different tools mounted on a plurality of tool rests and to simplify each shaft drive mechanism and a control mechanism through reduction of the number of control shafts. SOLUTION: An automatic lathe 10 is provided with a tool rest device 18 movably arranged on a machine bed 12 in front of a rotary main spindle 14, The tool rest device 18 comprises a slide 22 moved on the machine bed 12 in the direction of a Z1 axis paralleling the central axis of the rotary main spindle 14; a moving base 24 moved over the slide 22 in the direction of an Y-axis extending orthogonally to a Z1-axis; a first tool rest 26 moved over moving base 24 in the direction of an X-axis extending orthogonally to the Z1-axis and the Y-axis; and a second tool rest 28 moved over the moving base 24 in the direction of a Z2-axis independently from operation of the slide 22. The first tool rest 26 is provided in the front thereof with a plurality of cutting tools 70. The second tool rest 28 is provided in front thereof with a plurality of cutting tools 78. Under control of four axes in a total, the first and second tool rests 26 and 28 are driven independently from each other and simultaneous machining is executed on a material to be machined.