A memory device includes bit lines coupled to a memory block, a page buffer group selecting the bit lines in response to page buffer signals, applying a precharge voltage to selected bit lines from among the bit lines, and applying a ground voltage to unselected bit lines during a program verify operation, and a page buffer controller outputting the page buffer signals to selectively apply the precharge voltage to the bit lines according to an order of read operations on a logical page during the program verify operation.