A memory controller for performing garbage collection without moving data of a valid page, controls a memory device including a plurality of memory blocks in which data is stored. The memory controller includes a victim block setting circuit for selecting a victim block among the memory blocks by receiving memory block information representing whether a valid page and an invalid page are included in each of the plurality of memory blocks, when garbage collection is performed, and a sub-block controller for outputting a sub-block read command for determining valid pages included in each of sub-blocks within the victim block, by dividing the victim block into the sub-blocks, and outputting a sub-block erase command for selectively erasing a part of the sub-blocks included in the victim block, by receiving sub-block information corresponding to the sub-block read command from the memory device.