According to one embodiment, a semiconductor storage device includes strings each with a first select transistor, memory cell transistors, and a second select transistor connected in series. Word lines are provided, each connected to memory cell transistors in a same position across the strings. A bit line is connected in common to a first end of each of the strings. A source line is connected in common to a second end of each of the strings. A control circuit is configured to perform an erase operation on strings. The control circuit adjusts, for each of the strings, either an application time of a first voltage applied to a gate of the first select transistor of the respective string in the erase operation or a voltage level of the first voltage applied to the gate of the first select transistor of the respective string in the erase operation.