PROBLEM TO BE SOLVED: To play music from which a brain wave state desired by a user can be obtained.SOLUTION: A terminal device 12 receives designation of a brain wave state desired by a user, and controls play-back of music for making a transition of the user's brain wave state to the desired brain wave state or maintaining the desired brain wave state. The user's brain wave state is measured by an earphone device 10, and information indicating a result of the measurement is transmitted to the terminal device. In the terminal device, the measurement result is analyzed to evaluate the user's brain wave state; a sound signal is transmitted to the earphone device 10; music to be played is changed according to the brain wave state. Music data may be data provided to the terminal device from a music distribution server 14 or may be data stored in the terminal device.SELECTED DRAWING: Figure 1
INFORMATION PROCESSING APPARATUS, INFORMATION PROCESSING SYSTEM, AND PROGRAM