An endoscope processor comprising a signal receiver and a standard value calculator is provided. The signal receiver receives an image signal generated based on an optical image captured at a light receiving surface on an imaging device. The image signal comprises a plurality of pixel signals generated by a plurality of pixels according to amounts of received light. A plurality of the pixels are arranged on the light receiving surface. The standard value calculator calculates a standard value using a focused pixel signal and surrounding pixel signals. The surrounding pixel signals are the pixel signals of surrounding pixels. The surrounding pixels surround the focused pixel. The standard value is used for carrying out signal processing on the focused pixel signal.
