An intention estimated-weight determination processor 9 determines an intention estimated weight on the basis of an intention hierarchical graphic data 8 and an activated intention. A transfer node determination processor 10 determines an intention to be newly activated through transition, after correcting an intention estimation result according to the intention estimated weight. A dialog turn generator 13 generates a turn of dialog from the activated intention. A dialog management unit 2 controls, when a new input is provided due to the turn of dialog, at least one process among processes performed by an intention estimation processor 7, the intention estimated-weight determination processor 9, the transition node determination processor 10 and the dialog turn generator 13, followed by repeating that controlling, to thereby finally execute a setup command.