Flash memory device and programming method thereof

A flash memory device, comprising:

• a memory array, having a plurality of bit groups;
• and
• a memory control circuit, coupled to the memory array, and configured to sequentially perform a programming operation on the bit groups,
• wherein the memory control circuit performs one or more programming verification cycles on a target bit group in the bit groups when the target bit group fails a programming verification;
• the target bit group is divided into M parts, and M is a positive integer greater than 1;
• the memory control circuit determines whether the programming verification cycle performed on the target bit group is a first programming verification cycle, the memory control circuit sequentially programs the M parts with a first programming time when the first programming verification cycle is performed on the target bit group;
• and
• the memory control circuit simultaneously programs the M parts with a second programming time greater than the first programming time when the programming verification cycle other than the first programming verification cycle is performed on the target bit group.