An imaging device has a housing made of a first material having an open region, a first substrate for illumination arranged to cover the open region inside the housing, a second substrate for imaging arranged in parallel to the first substrate inside the housing, and a heat dissipating member made of a second material having a higher heat conductivity than the first material and being attached to a side surface of the housing so as to surround the open region of the housing. A concave is provided at the side surface of the housing, and the heat dissipating member includes a projection that fits to the concave.