In a semiconductor device comprising a ceramic substrate, a surface mount component, and sealing resin and obtained by division into pieces, the ceramic substrate is composed of a multiple piece substrate provided with dividing grooves for the division into pieces on both front and rear surfaces in advance, a plurality of the surface mount components are mounted on the multiple piece substrate and sealed collectively by the sealing resin, and the substrate is divided along the dividing grooves. Further, when the shortest distance from an end on the front surface of the ceramic substrate to an end of the surface mount component is set to “a” μm, a thickness of the ceramic substrate is set to “b” μm, and sum of depths of the dividing grooves on the front and rear surfaces of the ceramic substrate is set to “c” μm, a relationship of a≧269×c/b+151 is established.