The utility model relates to a laser quantitative power output controller, particularly a pen-shaped laser mark device. The laser quantitative power output controller comprises a laser light emitting body, a body seat, a contact switch device, a pen pushing device, a battery pack, a rotating cover, etc. A guide post of a contact button forces an elastic spring on a PC circuit plate to conduct a copper sheet circuit connected with the lower end of the PC circuit plate. The PC circuit plate outputs a quantitative power, which leads the output power for light spots to be stable. The utility model can be clamped by a pen to be hung on a pocket of a coat to be carried with a user.