Abstract: Disclosed is an LED flashlight using a high-luminance LED as a lamp. The LED flashlight has a conductive barrel, a conductive tail cap, and a head section. The head section includes a conductive head cap, an insulation case, a lamp module, first and second connecting conductors and a collimator lens. The conductive head cap is detachably coupled to a front end of the conductive barrel and has a transparent window. A front end of the insulation case is inserted into the head cap towards the transparent window. A slot is formed at an outer wall of the insulation case. The lamp module is assembled into an inner rear end of the insulation case and has an insulating substrate including an LED. An anode and a cathode electrode of the LED are formed at a peripheral portion of the lamp module. The lamp module has an insulating substrate formed at a rear surface thereof with a metal layer connected to a positive electrode of a battery.