The present invention provides an apparatus and method for photodynamic diagnosis and therapy of skin diseases and a light source system thereof that can improve the efficiency of skin diagnosis by accurately analyzing skin conditions using fluorescence and white light simultaneously and further carry out fluorescent diagnosis and photodynamic therapy in the same skin region simultaneously. The apparatus for photodynamic diagnosis and therapy of skin diseases of the present invention includes: a camera head including a case having a view hole, provided in front thereof, to be in contact with a skin region, a white light source provided so as to irradiate a white light from the inside of the case through the view hole onto the skin region, a digital color TV camera provided in the rear of the case, the camera head being provided to irradiate the white light, a fluorescence excitation light and a therapeutic light for the photodynamic therapy from the inside of the case onto the skin region being in contact with the view hole, and the digital color TV camera collecting the light from the skin region and outputting a generated image signal; a light source system, connected to the case of the camera head through a light guide capable of light transmission, for providing the fluorescence excitation light, the therapeutic light for the photodynamic therapy and the white light to be irradiated onto the skin region to the camera head; and an image processing and analysis system for receiving the image signal from the camera head to process, analyze and store to same, for displaying a color image by the white light, a fluorescence image by the excitation light and the therapeutic light for the photodynamic therapy, obtained by the digital color TV camera, and a synthesized image thereof, and for controlling the general operations of the camera head and the light source system.