The invention discloses a minitype nuclear battery, which mainly solves the problem that the nuclear battery manufacturing is easier than the SiC technology realization. A low doping epitaxial layer (2) and an ohmic contact electrode (3) are respectively arranged at the upper part and the lower part of an N-type high doping SiC substrate (1), wherein, a circular schottky contact layer (4) is deposited on the upper surface of the low doping epitaxial layer (2), and a SiO2 passivating layer (5) and a bonding layer (7) are arranged on the circumference at the outer edge of the schottky contact layer. The schottky contact layer (4) and a schottky contact electrode (6) are formed by adopting an identical technology, that is, a schottky contact hole is etched by adopting wet process in the center position of the SiO2 passivating layer (5), and Ni, Pt or Au with the thickness being 5 to 20 nm deposited on the SiO2 passivating layer on the hole or at the periphery of the hole, and the schottky contact layer (4) and the schottky contact electrode (6) are respectively formed after the SiO2 passivating layer is peeled off. The minitype nuclear battery has the advantages of simple technology and high conversion efficiency, and is applicable in directly converting the nuclear energy radiated by isotopes into the electric energy.