To realize a stable fuel pressure control which supresses the affection due to the deterioration with time of the fuel pump in a fuel supplying device which electrically controls the fuel pump.

Only when the cumulative driving time exceeds 500 hours and the travelling is steady-state, the sequence goes to the Step 107, the air/fuel ratio detected by the air/fuel ratio sensor is read in and, in the following Step 108, a judgement is made whether the air/fuel ratio is more rich or leaner than the target air/fuel ratio. When the air/fuel ratio is more rich than the target air/fuel ratio, the duty ratio Duty (%) which determines the control current value of the fuel pump is offset by C toward a fuel pressure reduction direction (Step 109) to reduce the fuel injection quantity for correcting the air/fuel ratio from rich to stoichiometric side. When the air/fuel ratio is leaner than the target air/fuel ratio, the duty ratio Duty is offset by C toward a fuel pressure increase side (Step 110) to increase the fuel injection quantity for correcting the air/fuel ratio from lean to stoichiometric side.