A locally illuminated keycap is located in a keyboard. The keyboard includes a lighting unit to project light to the keycap. The keycap includes at least one top edge to form an opaque press surface, at least one bottom edge located below the press surface to form a light incident surface to receive light, and at least one transparent light emitting surface connecting to the top edge and bottom edge to emit light. The press surface and light emitting surface form an inclined angle between them greater than 90 degrees. The press surface, light incident surface and light emitting surface jointly form a light retaining zone. Light generated by the lighting unit projects to the light incident surface and enters the light retaining zone, and is masked by the opaque press surface to emit locally through the transparent light emitting surface.