Provided are a semiconductor device having an MTJ element capable of intentionally shifting the variation, at the time of manufacture, of a switching current of an MRAM memory element in one direction; and a manufacturing method of the device. The semiconductor device has a lower electrode having a horizontally-long rectangular planar shape; an MTJ element having a vertically-long oval planar shape formed on the right side of the lower electrode; and an MTJ's upper insulating film having a horizontally-long rectangular planar shape similar to that of the lower electrode and covering the MTJ element therewith. As the MTJ's upper insulating film, a compressive stress insulating film or a tensile stress insulating film for applying a compressive stress or a tensile stress to the MTJ element is employed.