A silicon carbide semiconductor device having excellent performance characteristics and a method of manufacturing the same are obtained. A coating film made of Si is formed on an initial growth layer on a 4H—SiC substrate, and an extended terrace surface is formed in a region covered with the coating film. Next, the coating film is removed, and a new growth layer is epitaxially grown on the initial growth layer. A 3C—SiC portion made of 3C—SiC crystals having a polytype stable at a low temperature is grown on the extended terrace surface of the initial growth layer. A channel region of a MOSFET or the like is provided in the 3C—SiC portion having a narrow band gap. As a result, the channel mobility is improved because of a reduction in an interface state, and a silicon carbide semiconductor device having excellent performance characteristics is obtained.