An apparatus calculates, based on unimproved behavior amounts, behavior amount variations of living behaviors when each of living behaviors increases by one unit behavior amount, calculates environmental load variation of living behavior when the living behavior increases by one unit behavior amount, by calculating sum of values each obtained by multiplying one of behavior amount variations by corresponding one of basic units, to obtain environmental load variations of living behaviors, assigns messages to living behaviors based on environment load variations of living behaviors, calculates environmental load reduction of living behavior by (a) calculating variation between one of unimproved behavior amounts and one of improved behavior amounts of living behavior, and (b) multiplying variation by environmental load variation of living behavior, to obtain environmental load reductions of living behaviors, and selects one of messages which is assigned to one of living behaviors has the largest environmental load reduction.