A silicon carbide semiconductor device having an active layer with reduced defect density which is formed on a substrate made of silicon carbide, and a method of manufacturing the same are provided. A semiconductor device includes a substrate made of silicon carbide and having an off angle of not less than 50° and not more than 65° with respect to a plane orientation {0001}; a buffer layer, and an epitaxial layer, a p-type layer and an n+ region each serving as an active layer. The buffer layer is made of silicon carbide and formed on the substrate. The active layer is made of silicon carbide and formed on the buffer layer. The micropipe density is lower in the active layer than in the substrate. The density of dislocations in which the direction of a Burgers vector corresponds to is higher in the active layer than in the substrate.On the film forming conditions in the step of forming the buffer layer, the composition and the flow rate of the material gas is determined such that the value of the C/Si ratio representing a ratio of carbon atoms to silicon atoms in the material gas used for forming the buffer layer is smaller than the value of the C/Si ratio in the step of forming the active layer.