A radiation detector includes a sensor substrate, a conversion layer, and a neutral stress plane adjustment member. The sensor substrate includes a flexible base member, and a layer provided on a first surface of the base member and formed with plural pixels configured to accumulate electrical charge generated in response to light converted from radiation. The conversion layer is provided on the opposite side of the layer formed with the plural pixels to the side where the base member is provided and is configured to convert radiation into the light. The neutral stress plane adjustment member is provided on a second surface side of the base member on the opposite side of the base member to the first surface and is configured to adjust a position of a neutral stress plane to within a predetermined range in a stacking direction.