To eliminate risk of sudden change of flow rate and unstable flow rate control.

A fuel pressurizing pump is formed by connecting four small capacity pumps in parallel. When a second small capacity pump, a third small capacity pump, and fourth small capacity pump are started in an order in addition to a first small capacity pump, according to increase of load demanded for the fuel pressurizing pump, the small capacity pump to be newly started is started at output of 40% of individual rated output which is in a range where stable flow rate control can be done. Simultaneously, output of the small capacity pump which has been operating is reduced by 40% of the individual rated output. Increment of start output of the small capacity pump to be newly started is absorbed by the output reduction.