Pipe cutting machine

A pipe cutting machine comprises: rotary blades in a pair, with a plane at a right angle to a center line of a pipe, the rotary blades being arranged to face each other on both sides of a y axis in such a manner that blade edges of the rotary blades overlap each other in an x-axis direction; a straightforward driving mechanism that drives the rotary blades straightforward in opposite directions of a y-axis direction so as to make the rotary blades pass each other on the x axis and in the vicinity of the x axis; and power direction conversion mechanisms that move the rotary blades outwardly to get farther from the y axis for avoiding interference between the blade edges when the rotary blades pass each other on the x axis and in the vicinity of the x axis.