PURPOSE: To maintain a delivery amount to a fixed value, by providing a time changing means which changes the supply time of electric power in accordance with a decrease of electromotive force in a power source part consisting of a battery.

CONSTITUTION: A power source part 15, consisting of a battery for supplying power of driving a lubricant delivery mechanism 39, and a driving control means 43, controlling the time of supplying and stopping the power, are provided. While a time changing means 44, which changes the time of supplying the power in accordance with a change of electromotive force in the power source part 15, is provided. Accordingly, a power amount in each supply time is corrected to almost a fixed value by increasing the supply time longer by the decrease amount of the electromotive force. Consequently, the delivery amount of a lubricant can be maintained to almost a fixed value.