PURPOSE: To suppress displacement of air-fuel ratio by providing a switching means for switching a use map in accordance with a change of an exhaust circulation condition and a switching moderating means for gradually changing a fuel supply amount to a value, obtained after switching, from a value obtained by the map before switching.

CONSTITUTION: An intake pressure detecting means (b) and a fuel control means (c) for controlling a fuel supply amount from a fuel supply means (a) are provided and also providing an exhaust adjusting means (d) for changing an exhaust circulation condition followed by a change of exhaust pressure in accordance with an engine operative condition. A map for use of calculation of a fuel supply amount among a plurality of the maps of setting a corresponding relation between an intake pressure and the fuel supply amount is switched by a switching means (e) and used in accordance with a change of the above-mentioned exhaust circulation condition. In a fuel control device thus obtained, a switching moderating means (f) for gradually changing the fuel supply amount to a value, obtained by the map after switching, from a value, obtained by the map before switching, at the time of switching the map by the switching means (e) is provided. In this way, displacement of air-fuel ratio is prevented at transient time of changing the exhaust circulation condition.