A device for manufacturing a chopped fiber bundle includes a cutter roll provided with one or more disk blades on a circumference of a roll core having a center axis coinciding with a rotation axis of the roll core and a nip roll provided in parallel with the rotation axis of the roll core, to feed a reinforcing fiber yarn to be continuously cut between the nip roll and the cutter roll, further including a rotary drive mechanism that rotates the cutter roll and at least one of: a reciprocating drive mechanism that reciprocates the cutter roll along the rotation axis of the roll core; and a traverse guide that traverses the reinforcing fiber yarn along the rotation axis of the roll core.