According to one embodiment, a configuration memory includes first and second data lines, a first memory string which comprises at least first and second nonvolatile memory transistors which are connected in series between a common node and the first data line, a second memory string which comprises at least third and fourth nonvolatile memory transistors which are connected in series between the common node and the second data line, and a flip-flop circuit which comprises a first data holding node connected to the common node and a second data holding node connected to a configuration data output node.