A camera module is provided which has a simple structure, can be easily assembled, can avoid the adverse effects of dust on imaging, and can promote heat dissipation of an imaging device. In a camera module, which includes a lens unit that has a cylindrical thread portion, a flat plate-shaped imaging device that is mounted on a printed wiring board, and a holder that holds the lens unit and the printed wiring board with maintaining the predetermined positional relationship therebetween, an imaging field of the imaging device is disposed in a space tightly closed by a first spacer that is made into a ring shape made of an elastic material the surface of which is an adhesive surface, and the adhesive surface is exposed at least in an inner peripheral wall of the first spacer. The first spacer may be made of a material that further has favorable thermal conductivity.