1. A surveillance system based on accumulative features of an object, comprising: a storing unit that accumulatively keeps feature information of an object extracted from images taken by cameras; an object comparing unit that provides a new object feature information and existing object feature information matched at a predetermined level or more, by comparing the new object feature information about a new object extracted from an image taken by another camera having a surveillance area different from the surveillance areas of the cameras with existing object feature information about existing object accumulatively kept in the storing unit; an object mapping unit that identifies the existing and new objects in images corresponding to object feature information on the basis of the existing and new object feature information provided from the object comparing unit, and accumulatively stores the new object feature information as feature information about the existing object in the storing unit in accordance with user input for whether the identified existing and new object are the same or not; and an object identifying unit that automatically identifies the new object as an object the same as the existing object in the image taken by the another camera in combination with the object comparing unit, when there is existing object feature information matched with the new object feature information at a predetermined reference value or more.