Example embodiments may relate to a method and an apparatus for reading data stored in a memory, for example, providing a method and an apparatus for controlling a reference voltage based on an error of the stored data. Example embodiments may provide a memory data detecting apparatus including a first voltage comparator to compare a threshold voltage of a memory cell with a first reference voltage, a first data determiner to determine a value of at least one data bit stored in the memory cell according to a result of the comparison, an error verifier to verify whether an error occurs in the determined value, a reference voltage determiner to determine a second reference voltage that is lower than the first reference voltage based on a result of the verification, and a second data determiner to re-determine the value of the data based on the determined second reference voltage.