A memory device may include: a plurality of memory cells; a weak cell information storage unit suitable for storing a weak address and parity information corresponding to one or more weak cells having a shorter data retention time than a reference time, among the plurality of memory cells; an ECC (Error Correction Code) circuit suitable for detecting and correcting an error bit of the one or more weak cells using the parity information; and a refresh control unit suitable for controlling the plurality of memory cells to be refreshed at a cycle equal to or more than the reference time.