A technique capable of manufacturing a semiconductor device without posing contamination in a manufacturing apparatus regarding a phase change memory including a memory cell array formed of memory cells using a storage element (RE) by a variable resistor and a select transistor (CT). A buffer cell is arranged between a sense amplifier (SA) and a memory cell array (MCA) and between a word driver (WDB) and the memory cell array. The buffer cell is formed of the resistive storage element (RE) and the select transistor (CT) same as those of the memory cell. The resistive storage element in the memory cell is connected to a bit-line via a contact formed above the resistive storage element. Meanwhile, in the buffer cell, the contact is not formed above the resistive storage element, and a state of being covered with an insulator is kept upon processing the contact in the memory cell. By such a processing method, exposure and sublimation of a chalcogenide film used in the resistive storage element can be avoided.