A surplus amount of token calculating unit calculates a surplus amount of token for a station in which a residual amount of output buffer is smaller than a residual amount of token. A necessary amount of token calculating unit calculates a necessary amount of token for a station in which the residual amount of output buffer is larger than the residual amount of token. A token distributing unit distributes a token within a range of the surplus amount of token to a token counter of a station in which the necessary amount of token has been calculated, from a station in which the surplus amount of token has been calculated.