Alarm method and alarm system

An alarm system is provided with: an information acquisition unit (4) that acquires the heart rate and acceleration, which are biological information of a subject of interest (P1), and the temperature and humidity, which are environmental information of the surroundings of the subject of interest (P1); a risk level calculation unit (3) that calculates a risk level pertaining to heatstroke of the subject of interest (P1) on the basis of the heart rate, the acceleration, the temperature, and the humidity; and an alarm (5) that notifies an alarm on the basis of the calculated degree of risk. The alarm (5) changes the range of the alarm in accordance with the degree of risk. 警报系统具备：信息获取部(4)，其获取关注对象人(P1)的生物体信息即心率和加速度、以及关注对象人(P1)的周围的环境信息即温度和湿度；危险度计算部(3)，其基于心率、加速度、温度以及湿度来计算与关注对象人(P1)的中暑有关的危险度；以及警报器(5)，其基于计算出的该危险度的程度来通知警报。警报器(5)根据危险度的程度来变更警报的范围。