To stabilize a cutting start operation by securing suitable sliding between the edge of a rotary blade and the edge of a fixed blade without incurring an increase in a manufacturing cost due to complication of a manufacturing process.

A rotary cutter device 10 has a rotor 20 having a first flat blade 21 and a holding body 30 having a second flat blade 31 and starts cutting by sliding of a first blade edge part 21b of the first flat blade 21 and a second blade edge part 31b of the second flat blade 31 in a prescribed first rotational position by rotation of the rotor 20. A protrusion member 41 is provided on the rotor 20, the holding body 30 is moved by the protrusion member 41 in such a direction that the second blade edge part 31b is released from the rotational locus of the first blade edge part 21b at least before reaching the first rotational position, and the holding body 30 is moved in such a direction that the second blade edge part 31b approaches or invades the rotational locus of the first blade edge part 21b after the rotor 20 reaches at least the first rotational position.