To provide a radiator which can be made compact without lowering heat radiating performance by effectively blowing cooling air to a heat radiation portion close to a heat generating body.

On one side surface 2A of a heat reception plate 2 which comes into contact with the heat generating body 53 to receive heat, a plurality of heat radiating fins 3a, 3b and 3c are provided successively, and width-directional lengths L1, L2 and L3 of the heat reception plate 2 and heat radiating fins 3a, 3b and 3c are made gradually shorter with the distance from the center of the heat radiating body 53. Thus, the part of the heat reception plate 2, and heat radiating fins 3a, 3b and 3c which are distant from the center of the heat generating body 53 and hardly contribute to heat radiation is cut and then even when the cooling air is blown from an oblique direction of the heat radiating fins 3a, 3b and 3c, the cooling air is effectively blown to the heat radiating fin 3c to which heat from the heat generating body 53 is conducted first to effectively cool the heat conducted from the heat generating body 53, thereby enhancing heat radiation efficiency.