A structure for eliminating the noise in a light source device for an electronic endoscope safely eliminates the high-frequency noise produced from the lighting circuit, the xenon lamp and the like in the light source device. A capacitor for eliminating noise having a predetermined withstand voltage is connected between the support of the lighting circuit and the box body of the light source device so as to introduce the noise current produced by the switching operation of the lighting circuit to the ground. EMI springs are disposed between the outer peripheral surface of the conductive case of the lighting circuit and the xenon lamp and the inter peripheral surface of the box body of the light source device. A ferrite core for eliminating noise is provided on a conductive wire connecting the lighting circuit and the xenon lamp, thereby safely eliminating noise.