To provide a semiconductor device prevented from giving a limitation on the sensitivity of HEMS devices due to isolation regions thereof and a method of fabricating the same. The semiconductor device includes: a semiconductor substrate with a recess portion formed in an upper surface; a supporting body provided around the recess portion on the semiconductor substrate; a beam-type movable portion which includes a movable electrode provided above the recess portion and is fixed to the supporting body at a position away from the movable electrode; a beam-type fixed electrode provided above the recess portion to be opposed to the movable electrode and fixed to the supporting body; and isolation regions each including a separation column made of a semiconductor and a separation insulating film provided on a side surface of the separation column, the isolation regions being provided between the movable electrode and the supporting body and between the fixed electrode and the supporting body to electrically separate the movable and fixed electrodes from the supporting body.