An operating method of a nonvolatile memory device which includes receiving a plurality of sub-page data and a write command from an external device; performing a pre-main program operation such that at least one of the plurality of sub-page data is stored in the second plurality of memory cells included in the main region; performing a buffered program operation such that other received sub-page data is stored in the first plurality of memory cells included in the buffer region; and performing a re-main program operation such that the received sub-page data subjected to the buffered program operation at the buffer region is stored in the second plurality of memory cells subjected to the pre-main program operation.