1. An endoscope using depth information, the endoscope comprising: a light source to generate an irradiated light signal including a visible light; a sensor to obtain depth information, based on the irradiated light signal and a reflected light signal generated by the irradiated light signal being reflected off of an intestine wall of an intestine, to convert the reflected light signal to an electrical signal, to use signals obtained from phase converting of the irradiated light signal as a control signal for operating a switch, to measure an electric charge accumulated by the electrical signal in a capacitor connected to the switch for a plurality of phases, and to calculate a phase and an average strength of the reflected light signal based on the electric charge measured for the plurality of phases; and an image processor to generate a depth image inside the intestine wall based on the depth information, and to detect a polyp located on the intestine wall based on the depth image.