A circulation apparatus which causes blood of an examinee to circulate outside a human body by using a circulation circuit, the apparatus comprising: detecting means (115, 125) for detecting a status value related to blood while being provided on a flow path through which blood flows in the circulation circuit; determining means (110, 201) for determining whether or not a stable state in which the status value exhibits transition within a range (±ε) set in advance is achieved after the circulation circuit starts blood circulation; setting means for setting two threshold values (TH_H, TH_L) which respectively regulate an upper end and a lower end of a permissible state range based on the status value in the stable state when the determining means (110, 201) determines that the stable state is achieved; monitoring means for monitoring whether or not the status value is within the permissible state range which is regulated by the two threshold values (TH_H, TH_L), after the stable state is achieved; and warning means for issuing an alarm when the monitoring means detects that the status value deviates from the permissible state range; characterised in that the apparatus comprises second monitoring means for determining whether or not a differential value (Di) of the status value with respect to a time axis exceeds a threshold value range set in advance for a predetermined number of times in a row when the determining means (110, 201) determines that the stable state is achieved, wherein the warning means issues the alarm when the second monitoring means determines that the differential value (Di) of the status value with respect to the time axis exceeds the threshold value range for said predetermined number of times in a row. detecting means (115, 125) for detecting a status value related to blood while being provided on a flow path through which blood flows in the circulation circuit; determining means (110, 201) for determining whether or not a stable state in which the status value exhibits transition within a range (±ε) set in advance is achieved after the circulation circuit starts blood circulation; setting means for setting two threshold values (TH_H, TH_L) which respectively regulate an upper end and a lower end of a permissible state range based on the status value in the stable state when the determining means (110, 201) determines that the stable state is achieved; monitoring means for monitoring whether or not the status value is within the permissible state range which is regulated by the two threshold values (TH_H, TH_L), after the stable state is achieved; and warning means for issuing an alarm when the monitoring means detects that the status value deviates from the permissible state range; characterised in that the apparatus comprises second monitoring means for determining whether or not a differential value (Di) of the status value with respect to a time axis exceeds a threshold value range set in advance for a predetermined number of times in a row when the determining means (110, 201) determines that the stable state is achieved, wherein the warning means issues the alarm when the second monitoring means determines that the differential value (Di) of the status value with respect to the time axis exceeds the threshold value range for said predetermined number of times in a row.