An illumination control apparatus for being applied to a hand tool has a modulized structure and easy to be assembled and operated. The illumination control apparatus primarily comprises a modulized switch circuit, and a housing for enclosing the modulized switch circuit. By pressing a pressing switch of the modulized switch circuit, a light emitting element electrically connected to the modulized switch circuit can be controlled to provide or shut illumination thereof. Besides, the illumination control apparatus is firmly affixed to the hand tool by a screwing method.