An oil dilution inhibiting apparatus is mounted on a vehicle provided with an engine in which alcohol fuel can be used, the oil dilution inhibiting apparatus provided with: an intake amount integrating device for integrating amount of an air sucked into the engine while the engine is in operation, thereby calculating an integrated intake amount; a temperature detecting device for detecting oil temperature of engine oil of the engine; and a controlling device for controlling the vehicle to move into an oil heating mode in which the oil temperature is increased in such conditions that the calculated integrated intake amount is greater than an integrated intake amount threshold value and that the detected oil temperature is less than a first temperature threshold value.