To provide a machining device capable of machining even long workpiece with a large cross-section while reducing the waste of material, and machining various components with complicated shapes.

The machining device 1 includes: a gripping device 20 gripping and releasing the long workpiece W, and holding the workpiece in one posture without displacing in a state gripping the workpiece; and a main shaft of a rotary tool. The machining device 1 includes: a multi-axis robot 40 machining the workpiece gripped by the gripping device while projecting out a workpiece front end E from the gripping device by the rotary tool attached to the main shaft, and separating the machined workpiece front end from a non-machined part of the workpiece; and a workpiece feeding device 30 making the workpiece released from the gripping device move forward in a long axis direction.