There is provided a radiation detector using SiC and of a structure in which an electric field is applied to the interior of the entire SiC crystal constituting a radiation sensible layer, aiming to detect radiation while suppressing a reduction in electric signals generated in the radiation sensible layer.The radiation detector includes: a radiation sensible layer formed of silicon carbide and configured to generate an electron hole pair due to radiation entering it; a first semiconductor region in contact with a first principal surface of the radiation sensible layer and exhibiting a first impurity concentration at least in the region in contact with the radiation sensible layer; a second semiconductor region in contact with a second principal surface on the opposite side of the first principal surface and exhibiting a second impurity concentration at least in the region in contact with the radiation sensible layer; a first electrode connected to the first semiconductor region; and a second electrode connected to the second semiconductor region. The impurity concentration in the radiation sensible layer adjacent to the first semiconductor region, with the first principal surface serving as a border, is discontinuous with the first impurity concentration; the impurity concentration in the radiation sensible layer adjacent to the second semiconductor region, with the second principal surface serving as a border, is discontinuous with the second impurity concentration; and an electric field is applied to the entire radiation sensible layer in the depth direction thereof at a voltage during operation.