Memory data detecting apparatus and method for controlling reference voltage based on error of stored data

A memory data detecting device is provided to detect the data without an error by controlling a reference voltage based on the data error due to the change of a threshold voltage of a memory cell. A first voltage comparison unit(510) compares a threshold voltage of a memory cell with a first reference voltage. A first data deciding unit(520) decides a value of the data of at least one bit or more stored in the memory cell. An error generation determining unit(530) determines the generation of the error. A reference voltage determining unit(540) determines a second reference voltage lower than the first reference voltage based on the determination result. A second data determining unit(550) re-determines the value of the data based on the second reference voltage.