Provided is an information processing device that controls and presents sound information in an appropriate form to a user who acts in an environment on the basis of situation recognition including recognition of the environment and recognition of the actions of the user. The information processing device includes: a sensor that detects an object; an open ear style earpiece that is worn on an ear of a listener, and includes an acoustics generation unit, and a sound guide portion that transmits a sound generated by the acoustics generation unit into an earhole; and a processing unit that processes sound information of a sound source, the sound information being generated by the acoustics generation unit, the processing unit acquiring the sound information of the sound source corresponding to the object detected by the sensor, and a process of localizing a sound image of the acquired sound source while varying a position of the sound image in accordance with a position in a three-dimensional acoustic space, the position in the three-dimensional acoustic space corresponding to a position of the detected object.