A roller skating shoe with a light emitting device includes an elongate inverted U-shaped plate fixed under a skating shoe, a plurality of rollers combined rotatably with the elongate inverted U-shaped plate by means of two locating plates and bearings and rod shafts passing through the inverted U-shaped plate, the locating plates, and the rollers to be tightly screwed with anti-loose nuts. Coils are electrically connected with light emitters fixed on both sides of each roller. Magnets are fixed on the two locating plates producing magnetism to cross each coil to allow the coil to produce electricity to light up each emitter when the rollers are rotated by a skater.