Abstract: A self-illuminating coaxial knob provided on an operating panel of an air conditioning apparatus, an acoustic apparatus or the like, in which an outer knob and an inner knob connected to an outer shaft and an inner shaft, respectively, are coaxially provided on a panel surface, the panel being provided with a graduation, and the knobs being provided with indexes, respectively. The outer knob is illuminated from the back by a panel surface illuminating portion circularly provided on a panel surface light guide, whereas the inner knob is illuminated by a ring-like inner knob light guide provided in a ring-like incoming portion.