Abstract: An image sensor unit includes a light source that emits light, and a light guide that guides the light from the light source to an object to be illuminated. The light guide includes a linearly elongated rod-like rod portion provided with a light emission surface from which light is emitted to the object to be illuminated, and a curved portion which is integrally connected to an end in the longitudinal direction of the rod portion, includes a light entering surface where the light emitted from the light source is emitted on an end of a side opposite to the rod portion and in which the center line is curved. A reflection member that reflects light is provided to be in close contact with at least a part of a surface of the curved portion.