A method for manufacturing a honeycomb-structured object having a plurality of through holes having ends thereof plugged, including a step of pressing a plugging material against one end surface of a honeycomb-structured object 70 having a plurality of through holes 70a by a plate 20 to fill one ends of the through holes 70a with the plugging material; and a step of protruding a part of a portion in the plate 20 opposed to the one end surface of the honeycomb-structured object 70 toward the one end surface to pull the other part of the portion in the plate 20 opposed to the one end surface of the honeycomb-structured object 70 and the one end surface away from each other.