Semiconductor device

Disclosed are a fast, highly-integrated and highly-reliable magnetoresistive random access memory (MRAM) and a semiconductor device which uses the MRAM. The semiconductor device performs the read-out operation of the MRAM using memory cells for storing information by using a change in magnetoresistance of a magnetic tunnel junction (MTJ) element with a high S/N ratio. Each memory cell includes an MTJ element and a bipolar transistor. The read-out operation is carried out by selecting a word line, amplifying a current flowing in the MTJ element of a target memory cell by the bipolar transistor and outputting the amplified current to an associated read data line.