Provided is an apparatus and method for operating a flash memory according to a priority order, in which a fast response is insured. The apparatus includes a time calculation unit which calculates an operation execution time required to perform a first operation, a remaining time calculation unit which calculates a remaining time until completion of the first operation based on the calculated operation execution time if a second operation having a higher priority than that of the first operation is requested during performing of the first operation, and an operation processing unit which compares the calculated remaining time with an operation suspension time requested to suspend the first operation and determines whether to suspend the first operation in accordance with a result of the comparison.