Because hearing is restricted to one ear, people with unilateral hearing loss have difficulty in localizing sound sources and cannot recognize the direction of hazardous sounds, resulting in a delay in danger perception. To solve this problem, we aimed to develop a device that enables the brain of a person with unilateral hearing loss to recognize the direction of a hazardous sound. We created headgear with directional microphones and actuators at four locations around the head. As a result, the sound source localization signal and the hearing of the healthy ear were re-synthesized in the brain, and the sound source localization similar to that of the two healthy ears was achieved, with no loss of vision and a small-time lag, and the direction of sound could be taught. We were able to show the possibility of creating a device that can localize sound sources as well as the two healthy ears, without loss of vision and with a small-time lag.