An erase operating time can be shortened and an erase operating characteristic can be improved in a flash memory device. The flash memory device includes a plurality of memory cell blocks, an operating voltage generator and a controller. Each of the plurality of memory cell blocks includes memory cells connected to a plurality of word lines. A voltage generator is configured to apply an erase voltage to a memory cell block selected for an erase operation, and change a level of the erase voltage if an attempt of the erase operation is not successful. A controller is configured to control the voltage generator to apply a first erase voltage to a memory cell block selected for an erase operation. The first erase voltage corresponds to a previous erase voltage that was used successfully in completing a previous erase operation. The first erase voltage is an erase voltage that is used in a first erase attempt for the erase operation.