An image capturing base that contains a radiation detector includes a housing having a slit serving as an air inlet port formed in the front end side of the housing, which is to be located adjacent to the chest wall of a subject, and a slit serving as an air outlet port formed in the rear end side of the housing adjacent to a pivot shaft. A fan forces air to flow into the housing through the slit, along a detection surface of the radiation detector in a direction from the front end side toward the rear end side, and out of the housing through the slit.
