In order to objectively grasp the stress state of the user and prevent the mental illness of the user, the concentration of the heptadecane of the user acquired by the sensor that detects heptadecane released from the skin surface of the user is shown. The biogas information is acquired at a plurality of timings through a network together with time information corresponding to each time of the plurality of timings, and the normality is stored from a memory that stores information indicating the upper limit of the normal range of the heptadecane per unit period. The information indicating the upper limit of the range is read, based on the obtained biogas information, the time zone in which the concentration of heptadecane of the user exceeds the upper limit of the normal range is determined, and the information indicating the determined time zone is given to the user. Output to the information terminal.ユーザのストレス状態を客観的に把握し、ユーザの精神疾患を予防するために、ユーザの皮膚表面から放出されるヘプタデカン（Ｈｅｐｔａｄｅｃａｎｅ）を検出するセンサにて取得された前記ユーザのヘプタデカンの濃度を示す生体ガス情報を複数のタイミングで、前記複数のタイミングの各時刻に対応する時間情報と共にネットワークを介して取得し、単位期間当たりの前記ヘプタデカンの正常範囲の上限を表す情報を記憶するメモリから前記正常範囲の上限を表す情報を読み出し、前記取得した生体ガス情報に基づき、前記ユーザのヘプタデカンの濃度が前記正常範囲の上限を超える時間帯を判断し、前記判断された時間帯を示す情報を前記ユーザの情報端末に出力する。
