An internal combustion engine control method for controlling an internal combustion engine, wherein: - the internal combustion engine is equipped with: - an exhaust gas temperature variation factor unit (4; 5) that is configured to cause variations in a temperature of an exhaust gas of the internal combustion engine, - an exhaust heat recovery device that is configured to recover heat from the exhaust gas into a refrigerant that cools the internal combustion engine, and - a refrigerant pump that is configured to adjust a flow rate of the refrigerant that passes through the exhaust heat recovery device, characterized in that - the exhaust gas temperature variation factor unit (4; 5) includes a filter that is configured to collect particulate matter included in the exhaust gas, and - the exhaust heat recovery device is disposed in the exhaust passage downstream of the filter in a flow direction of the exhaust gas, and - the method comprises: - estimating a boiling margin, which is a parameter related to a thermal margin when the refrigerant boils in the exhaust heat recovery device and which is given as a difference between a boiling start temperature of the refrigerant and a refrigerant temperature at an outlet of the exhaust heat recovery device when regeneration control is carried out, and - prohibiting forced regeneration of the filter as a boiling avoidance process when the boiling margin is less than or equal to a threshold value. - the internal combustion engine is equipped with: - an exhaust gas temperature variation factor unit (4; 5) that is configured to cause variations in a temperature of an exhaust gas of the internal combustion engine, - an exhaust heat recovery device that is configured to recover heat from the exhaust gas into a refrigerant that cools the internal combustion engine, and - a refrigerant pump that is configured to adjust a flow rate of the refrigerant that passes through the exhaust heat recovery device, characterized in that - an exhaust gas temperature variation factor unit (4; 5) that is configured to cause variations in a temperature of an exhaust gas of the internal combustion engine, - an exhaust heat recovery device that is configured to recover heat from the exhaust gas into a refrigerant that cools the internal combustion engine, and - a refrigerant pump that is configured to adjust a flow rate of the refrigerant that passes through the exhaust heat recovery device, - the exhaust gas temperature variation factor unit (4; 5) includes a filter that is configured to collect particulate matter included in the exhaust gas, and - the exhaust heat recovery device is disposed in the exhaust passage downstream of the filter in a flow direction of the exhaust gas, and - the method comprises: - estimating a boiling margin, which is a parameter related to a thermal margin when the refrigerant boils in the exhaust heat recovery device and which is given as a difference between a boiling start temperature of the refrigerant and a refrigerant temperature at an outlet of the exhaust heat recovery device when regeneration control is carried out, and - prohibiting forced regeneration of the filter as a boiling avoidance process when the boiling margin is less than or equal to a threshold value. - estimating a boiling margin, which is a parameter related to a thermal margin when the refrigerant boils in the exhaust heat recovery device and which is given as a difference between a boiling start temperature of the refrigerant and a refrigerant temperature at an outlet of the exhaust heat recovery device when regeneration control is carried out, and - prohibiting forced regeneration of the filter as a boiling avoidance process when the boiling margin is less than or equal to a threshold value.