According to one embodiment, a nonvolatile semiconductor memory device includes: a first memory cell transistor; a first bit line; a first sense amplifier unit; a voltage generator; and a switch circuit. In a case where a power-supply voltage is equal to or lower than a first voltage and is higher than a second voltage when an access operation to the first memory cell transistor is started, the first sense amplifier unit is electrically disconnected from the first bit line and is electrically connected to the voltage generator via the switch circuit.