In a semiconductor storage device such as a phase change memory, a technique which can realize high integration is provided. The semiconductor storage device includes a phase change thin film 101 having two stable phases of a crystal state with low electric resistance and an amorphous state with high electric resistance, upper plug electrodes 102 and 103 provided on one side of the phase change thin film 101, a lower electrode 104 provided on the other side of the phase change thin film 101, a selecting transistor 114 whose drain/source terminals are connected to the upper plug electrode 102 and the lower electrode 104, and a selecting transistor 115 whose drain/source terminals are connected to the upper plug electrode 103 and the lower electrode 104, and a first memory cell is configured with the selecting transistor 114 and a phase change region 111 in the phase change thin film 101 sandwiched between the upper plug electrode 102 and the lower electrode 104, and a second memory cell is configured with the selecting transistor 115 and a phase change region 112 in the phase change thin film 101 sandwiched between the upper plug electrode 103 and the lower electrode 104.