The invention discloses a power tool and a lawn mower. They mainly include a functional device and a power device. The functional device is formed with a mounting portion for mounting the power device. The power device includes a prime mover and battery packs detachably coupled with a power housing. The prime mover can be a motor. The power housing is at least provided with an engaging portion allowing the power device to be at least mounted to the functional device, and a coupling portion for providing a space or structure for coupling with the battery packs. When the power device and the functional device constitute a whole through the mounting portion and the engaging portion, the battery packs at least can be detached from the power housing. The power tool of the invention uses multi battery packs to provide power, and the operation is convenient.
