To provide an imaging device that shows high resolution and high luminance and produces good-quality images, an imaging device includes phosphor layer having a thickness of 40 μm or less and containing a phosphor having a composition represented by chemical formula: Y2−x−yTbxScySiO5, wherein “x” and “y” are atomic ratios and satisfy the following conditions: 0<x≦1 and 0<y≦1. The phosphor preferably has a strongest diffraction peak at diffraction angle 2θ of 30.65° to 30.9° in X-ray diffraction for better properties. The phosphor can be prepared by firing a mixture of a compound containing Y, Sc, and Tb with a compound containing Si.