ROTATIONAL CUTTING DEVICE AND ROTATIONAL CUTTING METHOD

A rotary cutting apparatus 1 includes a pair of cutting tools each having a cutting blade 211 along a tip end of its outer peripheral portion 21 having a mountain-shaped cross section, and cuts a cylindrical material 80 into pieces with a predetermined width by sandwiching the cylindrical material 80 between the cutting blades 211 of the pair of cutting tools 2A, 2B so that the cutting blades 211 are respectively placed on inner and outer peripheries of the cylindrical material 80, and relatively rotating and moving the pair of cutting tools 2A, 2B along an entire circumference of the cylindrical material 80. In the rotary cutting apparatus 1, a second imaginary line L2 connecting an axial center A of the cylindrical material 80 and an axial center 02 of the inner peripheral-side cutting tool 2B is shifted in a circumferential direction C of the cylindrical material 80 about the axial center A of the cylindrical material 80 with respect to a first imaginary line L1 connecting the axial center A of the cylindrical material 80 and an axial center O1 of the outer peripheral-side cutting tool 2A.