To provide an assist device and an actuator device allowing an actuating means to be in the condition exerting an action to the surface as object easily and stably.

The assist device is equipped with a holding member 13 (holding part 29 and actuation part 28) and an arranging member 12. A cutting device 11 is equipped with the holding member 13 (holding part 29 and actuation part 28), the arranging member 12, and a cutting member 14. Therefore, the holding part 29 holds the cutting member 14, and the arranging member 12 arranges the holding part 29 over a paper surface PS, and when the actuation part 28 is depressed, the tip 42a of a blade is put in such a condition as biting into the paper P. Accordingly when a user uses this assist device (actuator device 11), for example in such a manner as putting his hand alongside the arranging member 12, the cutting member 14 can be put in the condition where the tip 42a of the blade bites into the paper P easily and stably.