An information signal reproducing apparatus which is capable of forming a suitable reproducing environment and building an easy-handling reproducing system regardless of differences such as signal format or recorded media of audio data to be reproduced is provided, in which: a medium type of an optical disc and signal format information of audio data to be read from the optical disc and to be reproduced are detected by an RF signal processing circuit and a Video/audio decoding unit so that a system control unit estimates whether the audio data to be reproduced is a music sound, a movie sound or another type of audio data in accordance with the detected information, and, in accordance with this estimation result, the system control unit and an interface control unit control an audio signal processing unit, an audio volume unit and a speaker amplifier unit so as to carry out a signal processing suitable for the audio data to be reproduced.