An apparatus and method of estimating the quality of an input signal, and an optical disc driver including the apparatus for estimating the quality of the input signal, the signal quality estimating apparatus including a level value detection unit that detects level values of an input signal according to a binary signal of the input signal, an input signal composing unit that composes a plurality of ideal input signals by using the level values and a plurality of pre-defined binary signals, and a quality calculation unit that obtains a quality of the input signal according to a calculation between the plurality of ideal input signals.