1. An apparatus for recognizing continuous speech using search space restriction based on phoneme recognition, the apparatus comprising: a speech feature extraction unit for extracting a feature vector from an input speech signal; a phoneme recognition unit for recognizing phonemes based on the feature vector of the speech signal; and a phoneme-based speech recognition unit for constructing a connection word search network having a restricted search space based on the phoneme recognition result to perform a speech recognition process based on the connection word search network.