To provide an image sensor cooling unit capable of efficiently cooling off a heat sources such as an image sensor, and being miniaturized without complicated assembling.

An image sensor cooling unit 30 includes an image sensor 21 fixed to and supported by an image sensor support plate 22, heat pipes 31 and 32 having heat dissipation function, and a thermoelectric conversion element 63 with both faces used as conductive heat transfer faces on which a first heat-conducting sheet 41 and a second heat-conducting sheet 42 are bonded. The thermoelectric conversion element 63 is pinched and supported while the first heat-conducting sheet 41 is bonded on a surface opposite to the imaging surface of the image sensor 21 and the second heat-conducting sheet 42 is bonded on a surface of the image sensor side of the heat pipes 31 and 32. In addition, thermal insulation materials 44 and 45 are interposed between the heat pipes 31 and 32 and the image sensor support plates 22. Moreover, a circulatory fluid passage is arranged.