Abstract: A flashlight includes a tubular barrel having an upper end formed with external threads and a lower end firmed with internal threads, a head having a lower end formed with internal threads adapted to engage with the external threads of the tubular barrel, an electrical socket fitted within the upper end of the tubular barrel, a light bulb having two depending electrodes received in the first and second holes of the electrical socket, a reflector arranged on the electrical socket and having a central opening for passage of the light bulb, a piece of glass arranged on the reflector, a tail having an upper end threadedly engage able a lower end of the tubular barrel, a water-proof cap mounted on a lower end of the tail, and a switch arranged within the tail and having a push button fitted in the water-proof cap, whereby the flashlight can be easily operated by depressing the switch at the tail.