A trench isolation type semiconductor device in which a recess is prevented from being formed in a field region and a method of fabricating the same are provided. The trench isolation type semiconductor device includes a semiconductor substrate defined by an active region and a field region, a trench formed in the field region, an oxide layer conformally formed along the inside of the trench, a liner layer conformally formed along the oxide layer, a field insulating layer formed inside the trench including the oxide layer and the liner layer, and a field protection layer formed on the field insulating layer so that a step difference does not occur on the semiconductor substrate.