A method for arbitrating data transfer requests from a plurality of nodes includes specifying one or more nodes among the plurality of nodes, the one or more nodes satisfying a predetermined condition, and selecting, if two or more nodes are specified among the plurality of nodes, one node from the two or more nodes using priority information, the priority information indicating correspondence between the plurality of nodes and a plurality of priorities each assigned to one of the plurality of nodes, the correspondence changing so that the plurality of priorities are assigned equally to each of the plurality of nodes and high and low relations appear equally between pairs of priorities each assigned to a pair of nodes of the plurality of nodes.