disclosed is a semiconductor device including : a semiconductor substrate ; first and second element isolating trenches that are formed in one main surface of the semiconductor substrate separately from each other ; a first insulating material that is formed within the first element isolating trench ; a plurality of first element formation regions that are surrounded by the first element isolating trench ; first semiconductor elements that are respectively formed in the first element formation regions ; a second insulating material that is formed within the second element isolating trench ; a second element formation region that is surrounded by the second element isolating trench ; a second semiconductor element that is formed in the second element formation region ; and a stress relaxation structure that is formed between the first element isolating trench and the second element isolating trench .