A control device of a cooling device controls a fan based on a desired temperature around a CPU set by a target value setting unit and a temperature detected by a temperature detecting unit, so that the temperature around the CPU substantially coincides with the set desired temperature. When the detected temperature exceeds the desired temperature, the control device causes the fan to rotate. At this time, the control device monitors the level of a noise generated by the fan by means of the noise detecting unit. The control device increases the value of the voltage supplied to the fan within a range in which the detected noise does not vary abruptly. As a result, the rotation speed is gradually increased to a predetermined value without causing an abrupt rise of a noise, which may acutely irritate the user.