A tube cutting apparatus includes an inner blade, a drive shaft, a coupling shaft, a planetary gear, and a ring gear. The outer blade has an inner peripheral surface which contacts an entire circumference of an outer periphery of a work W so as to cover a predetermined axial range of the outer periphery. The drive shaft is rotatably supported inside the work W coaxially with the work W and defines a bore therethrough at a position decentered by a predetermined amount within the drive shaft. The coupling shaft is rotatably supported in the bore. The inner blade is rotatably retained on an eccentric shaft decentered at a front end portion of the coupling shaft and is positioned inside the work W. The planetary gear is positioned outside the work W and fitted on a rear end portion of the coupling shaft coaxially and meshes with the ring gear.