A nonvolatile semiconductor memory device, having a booster circuit capable of performing a boost operation with appropriate boost voltage arrival time without increasing the circuit size. The nonvolatile semiconductor memory device includes a timing generator circuit and a current load circuit which applies a current load to an output of a booster unit according to a signal from the timing generator circuit, thereby achieving an appropriate boost voltage arrival time by using the current load circuit in concert with the operation of erasing or writing on memory cells.