We developed a method to control vibration from some blasting points. This method uses a correlation of vibration waves to decide the most effective delay time to control vibration by interfering vibration waves with each other. We applied this method to the small blasting using mortar blocks and examined the effect on controlling vibration. As the result of the examinations, the maximum vibration velocity by this method caused by five detonators blasting in row of five holes became smaller than that by a detonator blasting in the nearest hole from the measuring point. And the velocity was about one fifth of that of maximum condition in which vibration waves caused by the five detonators arrivved at the same time to the measuring point.