Provided is a programming method that increases writing performance of a flash memory device. The programming method for a flash memory device that includes a plurality of banks including a plurality of memory cells for storing multi-bit data includes the following: programming a most significant bit (MSB) page with respect to banks of a first bank group; programming a least significant bit (LSB) page with respect to banks of a second bank group; programming the MSB page with respect to the banks of the second bank group; and programming the LSB page with respect to the banks of the first bank group.