PURPOSE: To achieve writing in a short time by applying a collective current to a P+ region formed in a part of an emitter-base junction.

CONSTITUTION: When a writing pulse may be applied to the intermediate line between an emitter electrode E of a selected memory cell and a word line current absorption terminal C so that the junction face between an emitter region 17 and base region 14 is biased reversely, almost of the writing current is directed to a collector region 13 and N+-type buried layer 12 through a P+region adjacent to the emitter region 17. Therefore, the writing can be established by breaking down the P-N junction of the contact portion between the emitter region 17 and P+ 15. In this case, because the area of the contact portion of the emitter region 17 with the P+ region 15 can be reduced, the collection of the current is easily caused and a break-down is frequently occurred.