The sound reproducer (100) generates and outputs, when any external situation such as a running sound is recognized by an external input rhythm detecting section (110), generates external rhythm information concerning the recognized running sound. When the external rhythm information is acquired, a rhythm setting section (173) of a processing section 170) generates set rhythm information for setting a rhythm of a music corresponding to the rhythm of the running sound. Because of this feature, even when a running state of the vehicle changes, the sound reproducer (100) can reproduce a rhythm of a music with a rhythm corresponding to the running state. Because of this feature, the music can be reproduced in better conditions in correspondence to the external situation.