A focusable flashlight comprising a cylindrical tube for containing a battery, a head combined with the front end of the tube by means of a spring stop, a lamp holder and a spring pusher, the head functioning as a switch by being movably screwed to change the distance between the lamp holder and the front end surface of the tube in turning on or off electric power from the battery and at the same time light focusable by means of a transparent lens and a light reflector fixed at the front of the head.