A nailer with an illumination device located adjacent to the muzzle thereof comprises a nailer and an illumination device. The nailer has a muzzle defined at a front end of a housing thererof, between the muzzle and the housing is arranged a panel and a protection hood covered on the panel, and on the protection hood is formed a notch aligned with the muzzle. Beneath the protection hold is disposed a circuit board, on the circuit board is battery. A positioning hole is defined in a side of the protection hood facing the housing. A buffer is disposed in the positioning hole of the protection hood in such a manner that a part of the buffer protrudes out of the positioning hole and is to be pressed against the housing. The illumination device is disposed beneath the protection hood of the nailer and located correspondingly to the notch.