An image detection device includes a sensor panel and a light. The sensor panel includes a semiconductor layer, which is formed on a substrate formed of a member having a light transmitting property and generates charges in response to X-rays radiated thereto, two pairs of electrodes each pair disposed in confrontation with each other, and a plurality of accumulating portions formed between the semiconductor layer and the substrate to accumulate the charges generated to the semiconductor layer as the information of the pixels constituting an image. The light radiates light to the surface of the sensor panel on the substrate side thereof. The respective electrodes of the accumulating portions are formed so that light having at least a predetermined intensity is radiated from the light to the regions of the semiconductor layer where the accumulating portions are formed.