Disclosed is a cell voltage monitoring apparatus for monitoring output voltages of a plurality of unit cells in a cell having the unit cells. The cell voltage monitoring apparatus includes: a reference voltage generator for generating a predetermined reference voltage from the unit cell generation voltage; a voltage comparator for comparing a generation voltage of a monitor unit cell and the reference voltage; a signal separator for outputting a signal that is electrically separated from an output signal of the voltage comparator; and an operation processor for determining normality of the cell voltage from a signal output by the signal separator.