A chronic heart failure diagnosis device for use by a medical professional to observe changes in clinical conditions of a patient with chronic heart failure and for diagnosis, comprising: one or more detection means for continuously detecting one or more different physiological indexes of the patient, and a means for generating information to generate and output information, wherein the means for generating information is constituted so that A) during a first observation period which includes a functional stage of the compensatory mechanism or the observation period in which the functional stage of the compensatory mechanism is suspected to be working, one or more indexes including at least one of the augmentation stage of the sympathetic nerve, vasoconstriction, and at least one of respiratory frequency, index indicating the respiratory stability and the amount of ventilation are continuously observed, and when a significant change is found in any of them, or when a combination of them appears according to a first predetermined rule, alert signals are generated, and B) during a second observation period which includes a breakdown stage in which the pump function in the heart is found to be so low that the compensatory mechanism cannot catch up with it or the observation period which is suspected to be at the breakdown stage, one or more indexes including at least one of the cardiac output, blood pressure, oxygen saturation in blood, at least one of respiratory frequency, an index of respiratory stability and the amount of ventilation or the arrhythmic state are continuously observed, and when significant changes are found in any of them, or when a combination of them appears according to a second predetermined rule, alert signals are generated. one or more detection means for continuously detecting one or more different physiological indexes of the patient, and a means for generating information to generate and output information, wherein the means for generating information is constituted so that A) during a first observation period which includes a functional stage of the compensatory mechanism or the observation period in which the functional stage of the compensatory mechanism is suspected to be working, one or more indexes including at least one of the augmentation stage of the sympathetic nerve, vasoconstriction, and at least one of respiratory frequency, index indicating the respiratory stability and the amount of ventilation are continuously observed, and when a significant change is found in any of them, or when a combination of them appears according to a first predetermined rule, alert signals are generated, and B) during a second observation period which includes a breakdown stage in which the pump function in the heart is found to be so low that the compensatory mechanism cannot catch up with it or the observation period which is suspected to be at the breakdown stage, one or more indexes including at least one of the cardiac output, blood pressure, oxygen saturation in blood, at least one of respiratory frequency, an index of respiratory stability and the amount of ventilation or the arrhythmic state are continuously observed, and when significant changes are found in any of them, or when a combination of them appears according to a second predetermined rule, alert signals are generated. A) during a first observation period which includes a functional stage of the compensatory mechanism or the observation period in which the functional stage of the compensatory mechanism is suspected to be working, one or more indexes including at least one of the augmentation stage of the sympathetic nerve, vasoconstriction, and at least one of respiratory frequency, index indicating the respiratory stability and the amount of ventilation are continuously observed, and when a significant change is found in any of them, or when a combination of them appears according to a first predetermined rule, alert signals are generated, and B) during a second observation period which includes a breakdown stage in which the pump function in the heart is found to be so low that the compensatory mechanism cannot catch up with it or the observation period which is suspected to be at the breakdown stage, one or more indexes including at least one of the cardiac output, blood pressure, oxygen saturation in blood, at least one of respiratory frequency, an index of respiratory stability and the amount of ventilation or the arrhythmic state are continuously observed, and when significant changes are found in any of them, or when a combination of them appears according to a second predetermined rule, alert signals are generated.