A fuel supply control device for an internal combustion engine having an exhaust supercharger, the fuel supply control device comprising: a fuel injector that injects fuel into a cylinder directly; judging means for judging whether a shortage of an actual engine output against a required output is larger than a predetermined permissible limit; and increasing means for supplying auxiliary fuel from the fuel injector at a power stroke after main fuel is supplied, to temporarily increase an exhaust energy, which is energy of the exhaust gas flowing into the exhaust supercharger, when the judging means judges that the output shortage is larger than the permissible limit, the fuel supply control device further comprising: suppressing means for judging whether an increase of the exhaust energy using the auxiliary fuel is to be suppressed, and for reducing a supply amount of the auxiliary fuel when it is judged that the increase of the exhaust energy using the auxiliary fuel is to be suppressed, wherein the suppressing means comprises an exhaust emission amount predicting means for predicting an exhaust emission amount assuming the auxiliary fuel is supplied, and wherein the suppressing means judges that the increase of the exhaust energy using the auxiliary fuel is to be suppressed when the predicted exhaust emission amount is larger than a set exhaust emission amount determined in advance, and characterized in that a particulate filter for collecting particulates contained in the exhaust gas is disposed in an exhaust path of the internal combustion engine, wherein the suppressing means comprises means for, when the predicted exhaust emission amount is smaller than the set exhaust emission amount, obtaining an increment of the collected amount of particulates on the particulate filter assuming that the supply of the auxiliary fuel is stopped and for also obtaining a change rate of the increment, and wherein the suppressing means judges that the increase of the exhaust energy using the auxiliary fuel is to be suppressed when the obtained change rate of the increment is larger than a set change rate determined in advance. a fuel injector that injects fuel into a cylinder directly; judging means for judging whether a shortage of an actual engine output against a required output is larger than a predetermined permissible limit; and increasing means for supplying auxiliary fuel from the fuel injector at a power stroke after main fuel is supplied, to temporarily increase an exhaust energy, which is energy of the exhaust gas flowing into the exhaust supercharger, when the judging means judges that the output shortage is larger than the permissible limit, suppressing means for judging whether an increase of the exhaust energy using the auxiliary fuel is to be suppressed, and for reducing a supply amount of the auxiliary fuel when it is judged that the increase of the exhaust energy using the auxiliary fuel is to be suppressed, wherein the suppressing means comprises an exhaust emission amount predicting means for predicting an exhaust emission amount assuming the auxiliary fuel is supplied, and wherein the suppressing means judges that the increase of the exhaust energy using the auxiliary fuel is to be suppressed when the predicted exhaust emission amount is larger than a set exhaust emission amount determined in advance, and characterized in that a particulate filter for collecting particulates contained in the exhaust gas is disposed in an exhaust path of the internal combustion engine, wherein the suppressing means comprises means for, when the predicted exhaust emission amount is smaller than the set exhaust emission amount, obtaining an increment of the collected amount of particulates on the particulate filter assuming that the supply of the auxiliary fuel is stopped and for also obtaining a change rate of the increment, and wherein the suppressing means judges that the increase of the exhaust energy using the auxiliary fuel is to be suppressed when the obtained change rate of the increment is larger than a set change rate determined in advance.