To provide a long material cutter which can cut a long material at a high speed and also by which the finish of a cut surface becomes favorable.

A long material cutter is provided with a cutting motor 30 for rotating and driving a cutting edge 181, a crank mechanism which can adjust the eccentric amount r of a crank, a slider 12 attached with the cutting edge 181 and also driven by the cutting motor 30 through the crank mechanism to move in parallel with a workpiece (tube 81), an eccentric position adjust means 50 for changing the eccentric amount r, the move sensor 69 of the workpiece, a rotation judging means of the rotation position of the cutting motor, and a control means 60, which can change the eccentric amount r while the rotation edge cuts the workpiece and control the eccentric position adjust means so that the moving speed vs of the slider is nearly the same as the moving speed vt of the workpiece.