PURPOSE: To provide a pipe cutter capable of easily cutting a large-diameter pipe having an obstacle with a simple mechanism.

CONSTITUTION: This pipe cuter is provided with a rotary head 3 having an outer diameter smaller than the inner diameter of a pipe 13 to be cut and rotatively driven by a motor 1 via a rotary shaft 2 and head holding devices 11 arranged with the rotary head 3 rotatably and nearly concentrically in the pipe 13. A wire saw 7 is fixed along the outer peripheral edge of a base plate 6 having a circular arc-shaped outer peripheral edge. The pipe cutter is constituted of multiple cutting members 4 rockably supported on the rotary head in the plane perpendicular to the rotary shaft 2 so that the wire saw 7 can pass through the cutting area from the inner wall of the pipe 13 to the outer wall and pressurizing means exciting the cutting members 4 so that the wire saw 7 is moved from the inner wall of the pipe 13 to the outer wall.