An endoscopic terminal processor for an electronic endoscope, which accommodates within its casing an illumination light source along with a video signal processor for an electronic endoscope. A circuit board of the video signal processor is supported compactly in an upright position within the casing, and fixedly connected at one end to an inner surface of a side panel of the casing, and loosely supported at the other free end on a damper member adapted to restrict flapping movements of the circuit board about the fixed end and to permit movements in other directions to some extent to evade collisional impacts or shocks which might be transmitted from the casing.