An imaging device which is highly stable to irradiation with radiations such as X-rays and can inhibit a decrease in electrical characteristics is provided. The imaging device obtains an image using radiations such as X-rays and includes pixel circuits which are arranged in a matrix and which a scintillator overlaps. Each of the pixel circuits includes a switching transistor whose off-state current is extremely low and a light-receiving element. A shielding layer formed using a metal material and the like overlaps the transistor and the light-receiving element. With the structure, an imaging device which is highly stable to irradiation with radiations such as X-rays and can inhibit a decrease in electrical characteristics can be provided.