According to an embodiment, a semiconductor device includes a control circuit. The control circuit is configured to receive a first command and execute, based on the first command, a first operation and a second operation. The second operation is executed after the first operation. The control circuit is further configured to output a first signal from a start of the first operation to a start of the second operation. The first signal indicates that the semiconductor device is in a busy state in which the semiconductor device refrains from accepting, from an external controller, a second command for execution of the first operation and a third command for execution of the second operation.