A semiconductor nonvolatile memory device of an embodiment includes: a plurality of transistors arranged in a matrix, the transistors in the same row being connected in series to form a transistor string having a first terminal and a second terminal; a plurality of first wiring lines each corresponding to one of the columns, and being connected to the gates of the transistors of the corresponding column; a common first electrode connected to each semiconductor region in which each transistor is disposed; and a write unit that selects one of the first wiring lines and one of the transistor strings, and applies a first voltage to the first electrode, a first write voltage to the selected first wiring line, a second voltage to the other first wiring lines, and a second write voltage to the first terminal and the second terminal of the selected transistor string in a write operation.