Abstract: Provided are an apparatus and method for speech segment detection, and a system for speech recognition. The apparatus is equipped with a sound receiver and an image receiver and includes: a lip motion signal detector for detecting a motion region from image frames output from the image receiver, applying lip motion image feature information to the detected motion region, and detecting a lip motion signal; and a speech segment detector for detecting a speech segment using sound frames output from the sound receiver and the lip motion signal detected from the lip motion signal detector. Since lip motion image information is checked in a speech segment detection process, it is possible to prevent dynamic noise from being misrecognized as speech.