A portable endoscope having a light guide for transmitting light to illuminate an object. The light guide has an entrance end portion disposed in a control part. An illuminating light supply unit contains a power supply for supplying the illuminating light to the light guide. The illuminating light supply unit is detachably connected to the control part. A lamp serving as a light source of the illuminating light is provided such that when the illuminating light supply unit is detached from the control part, the lamp is left in the control part.