Abstract: An illuminating device for a pair of glasses includes an illumination control device, a housing, a coupling seat, and a positioning mechanism. The illumination control device is received in the housing and includes a lamp emitting light beams out of the housing. The coupling seat includes first and second pivotal portions. The housing is pivotably coupled with the first and second pivotal portions, so that the housing is pivotable relative to the coupling seat. The coupling seat further includes a coupling section coupled to a middle of the pair of glasses. The positioning mechanism retains the housing in a desired angular position relative to the coupling seat, adjusting an illuminating angle of the lamp.