A laser device is provided. The laser device includes: a laser tube having an opening in both ends thereof, and a fixing apparatus on at least one of the ends of the laser tube. The opening in at least one of the ends of the laser tube is sealed by the fixing apparatus. A movable assembly and a window are provided on the fixing apparatus. The window is movable relatively to the opening of the laser tube when being driven by the movable assembly, to change a transmission position of a laser light generated by the laser tube on the window.