Effect adding system and method for multi-projection

The present invention relates to a side-effect system and method for the screening, if a plurality of the projection surface provided in a single auditorium; And comprising the additional effect of apparatus for implementing an additional effect other than the image projected on the projection surface of the plurality, the side-effect device, that make different the direction of the side-effect depending on the image being projected to the plurality of projection surface and that is characterized.