To cut a pipe extruded out of an extruding machine in a regular size with high accuracy with no impact given in a cutting device to be used for a pipe extrusion molding process.

In this device provided with a cutting edge capable of cutting a pipe P, chuck mechanisms 5a and 5b are mounted to a cutter unit 2 so set up as to be freely moved in parallel with the pipe extruding direction by way of cushioning mechanisms 7a and 7b formed out of elastic members 72 in which cylinders 71 and springs are built. The chuck mechanisms 5a and 5b holding the pipe P are moved horizontally by means of the cylinders 71, then they abut against the elastic members 72 so as to gradually transmit force extruding the pipe P to the cutter unit 2, so that impact against the held face of the pipe P can thereby be prevented.