A parison separation device (30) according to an embodiment includes a cutter (31) with a cutting edge (35), the cutting edge (35) extending in a one direction and facing upward, and a block (33), the cutter being attached to an upper part of the block (33), inclined surfaces (37) being formed on both sides of the block (33) in a thickness direction of the cutting edge (35), each of the inclined surfaces (37) including a component that is inclined increasingly downward as it gets closer to one direction side end, in which the parison separation device (30) is disposed on a discharging direction side of a discharging port of a parison and configured to cut the parison discharged from the discharging port.