A cooling device for an internal combustion engine, comprising: a first cooling water flow channel (34, 35) formed in a main unit of the internal combustion engine; intake air cooling means of a water cooling type configured to cool an intake air; a first cooling water circulating system configured to circulate a first cooling water in the first cooling water flow channel (34, 35); a second cooling water circulating system (10, 50, 60) that is separate from the first cooling water circulating system and is configured to circulate a second cooling water at a lower temperature than the first cooling water through the intake air cooling means; and a controller that is configured to control operation of the second cooling water circulating system (10, 50, 60) in accordance with a load and an engine speed of the internal combustion engine and a temperature of the first cooling water, characterized in that the controller is configured to control operation of the second cooling water circulating system (10, 50, 60) so as to set the temperature of the second cooling water lower in a case where an operating point of the internal combustion engine, that is defined by the load and the engine speed, lies in a particular region of an operational region of the internal combustion engine, the particular region including a region in which the load is high and the engine speed is low, than in a case where the operating point lies outside of the particular region, and narrow the particular region in a direction toward higher loads in a case where the temperature of the first cooling water is lower than a predetermined temperature compared with a case where the temperature of the first cooling water is higher than the predetermined temperature. a first cooling water flow channel (34, 35) formed in a main unit of the internal combustion engine; intake air cooling means of a water cooling type configured to cool an intake air; a first cooling water circulating system configured to circulate a first cooling water in the first cooling water flow channel (34, 35); a second cooling water circulating system (10, 50, 60) that is separate from the first cooling water circulating system and is configured to circulate a second cooling water at a lower temperature than the first cooling water through the intake air cooling means; and a controller that is configured to control operation of the second cooling water circulating system (10, 50, 60) in accordance with a load and an engine speed of the internal combustion engine and a temperature of the first cooling water, characterized in that the controller is configured to control operation of the second cooling water circulating system (10, 50, 60) so as to set the temperature of the second cooling water lower in a case where an operating point of the internal combustion engine, that is defined by the load and the engine speed, lies in a particular region of an operational region of the internal combustion engine, the particular region including a region in which the load is high and the engine speed is low, than in a case where the operating point lies outside of the particular region, and narrow the particular region in a direction toward higher loads in a case where the temperature of the first cooling water is lower than a predetermined temperature compared with a case where the temperature of the first cooling water is higher than the predetermined temperature.