To provide a workpiece supply device (30) capable of supplying a workpiece (W) to be machined next in a supplying area of the workpiece (W) outside a machining area while the machining area is closed to control scattering of cutting fluid from the machining area during the machining of the workpiece (W). A machine tool (100) includes a machining room (2) of the workpiece (W), a loader room (3), a dividing wall (4) having an opening part (5), a main spindle (10), a workpiece supply device (30), a delivery device (20), and an ejection device (60). The workpiece supply device (30) includes a workpiece holder (31), a movement mechanism (32), a cover member (33), and a coil spring (40). The coil spring (40) biases the cover member (33) to close the opening part (5) by the cover member (33) such that the workpiece holder (31) holds the workpiece (W) in the loader room (3) during the machining of the workpiece (W) in the machining room (2).