Abstract: A press-key with low light diffusing design, adapted to be received inside a frame of a keyboard, is disclosed, which comprises: a substrate; a keycap, formed with a light-transmissive part, being mounted on the substrate while enabling the same to move vertically up and down in relative to the substrate; a light-emitting unit, disposed inside the keycap at a position below the light-transmissive part; and a light mask, made of an opaque material and being formed as an upward-extending wall surrounding the circumference of the light-emitting unit while allowing an opening to be formed on top thereof at a position corresponding to the light-transmissive part and thus allowing the light emitted from the light-emitting unit to be projected out of the light mask only through the opening of the same and thus to be emanating out of the keycap only through the light-transmissive part.