A diagnostic imaging apparatus of hand piece type suitable for medical or dental use, comprising a main body held by operator's fingers, a luminous means for irradiating at least one of lights selected from excitation light, infrared light and ultraviolet light, and an imaging means provided in a forward portion of the main body. The imaging means comprises a solid-state image sensing device and an optical means for forming an optical image of a diagnosis object to be examined on the solid-state image sensing device and is so constructed as to output a predetermined diagnostic image information by receiving the light reflected from the diagnosis object and/or the fluorescence generated from the diagnosis object when irradiation of light from the luminous means to the diagnosis object is performed.