An LED light source applied to surveillance cameras as an infrared source or a visible-light source has a light emitting diode (LED) as the light emitting mechanism. The LED chip is mounted on a surface of a metallic body of high thermal conductivity, the surface being planar for scattering light or convex for collimating light. The heat produced in the LED chip is quickly guided to a heat-sink structure much massive than the chip and having large contact area with a heat radiating structure, thereby effectively dissipating the heat and increasing the power capacity of the chip. The heat-sink structure has a plurality of elongated heat conducting members confined by an insulating bracket at one end and mounted on a metallic base on the other end. The metallic base can be coupled with a heat radiator to enhance heat radiation.