Provided are a semiconductor device including a desired snubber part in accordance with use of the semiconductor device and a method of manufacturing the semiconductor device. A snubber region having a snubber part is defined in a gate pad region defined on a side close to a first main surface of a semiconductor substrate. A p-type diffusion layer and an n-type column layer contacted to each other are formed in the snubber region. The p-type diffusion layer and the n-type column layer are formed as a parasitic capacitance of the snubber part while the n-type column layer is electrically coupled to a drain. The p-type diffusion layer, which extends in a Y-axis direction, is a resistance of the snubber part and electrically coupled to a source.