A memory management method configured for a rewritable non-volatile memory module, a memory storage device, and a memory control circuit unit are provided. The rewritable non-volatile memory module includes a plurality of dies, wherein each of the dies includes a plurality of planes, each of the planes includes a plurality of physical erasing units, and a sum of a number of the planes included in the rewritable non-volatile memory module is a first number. The method includes: grouping the plurality of physical erasing units into a plurality of management units. Each of the plurality of physical erasing units included in each of the management units belongs to a different plane, and each of the management units has a second number of the physical erasing units, wherein the second number is less than the first number.