In connection with a write operation, a memory controller transmits a first command sequence to a memory chip, thereby causing the memory chip to execute a first-stage program operation that includes a first operation and a first part of a second operation after the first operation, and a second command sequence to the memory chip after the first-stage program operation is executed, thereby causing the memory chip to execute a second-stage program operation that includes a second part of the second operation and no part of the first operation. During the first operation, a program voltage is applied a plurality of times while increasing the program voltage each of the times by a first step size. During the second operation, the program voltage is applied a plurality of times while increasing the program voltage each of the times by a second step size smaller than the first step size.