An image storage device based on an input sound signal comprises: an acceleration sensor unit for outputting an acceleration sensor value according to an impact event; a microphone unit for receiving an input of an impact sound according to the impact event; a camera unit for photographing an external image; and a processing unit for, if an impact event is sensed by the acceleration sensor unit and the impact sound inputted by the microphone unit corresponds to a valid sound which is previously set and stored, storing, in a storage unit, the images photographed by the camera unit in a certain time period both before and after the point in time when the impact event occurred.