To enable a lot of audio data and image data such as a still image and a moving image to be effectively and efficiently used. When audio data accumulated in a material database 21 is replayed, a controller 10 acquires the metadata added to the audio data to be replayed from the material database, refer to the metadata of image data based on the above metadata to thereby search image data intimately related to the audio data, controls a voice replay system such as an audio decoder 32 and the like and an image replay system such as an image decoder 31 and the like, and replay the audio data to be replayed and the searched image data in relation with each other.