To provide a press cutting device of a pipe and its method, which can prevent deformation of a cut edge part of the pipe, cut the pipe in a state having a good-looking cut edge, and extend the life having less wear of movable blade for shearing.

The cutting device is equipped with a side cutting blade 1 which cuts a head part of the pipe in the peripheral direction to form a slit S, a pair of cutting blades 2a, 2b for expanding which cut both end parts of the slit S while expanding cutting chips p1, p2 to the outside of the pipe P respectively, by sequentially inserting in a crossing shape respectively from the oblique direction in the slit S, and an approximately triangle shape movable blade 3 for shearing which shears the pipe P between the movable blade 3 and a fixed blade 4 disposed in a state pinching a pipe cutting part by inserting in the slit S where both end parts are expanded to the outside.