To cut a tubular item in a desired length simultaneously as it is processed to be expanded so as to simplify tubular item manufacturing work, and to reduce an occupied space.

The expanded tube cutting device 10 is provided with 8 inner blade dies 1, an outer blade 2, and a cone 38. The outer blade 2 has a similar circular form of which inner circumferential surface is similar to the outer circumferential surface of the tubular item 100 before it is expanded. A side surface 21 is set close to a cutting position S to be fitted with the tubular item 100 outside of it. Each inner blade die 1 is the one equally divided along the circumference of a cylindrical form to be disposed inside the tubular item 100 at a prescribed interval from the side surface 21 of the outer blade 2 on both sides of the cutting position S in the X-axis direction. The outside surface of each inner blade die 1 is composed of an arc surface of smaller diameter than the inner diameter of the tubular item 100 before it is expanded. The inside surface is composed of an inclination surface 13 inclined along the X-axis direction. The outside surface of the cone 3 is abutted on the inside surface of the inner blade die 1. The cone 3 is moved in the X-axis direction to move the inner blade dies 1 radially outward at similar speed to each other.