A first combustion mode (I) in which the amount of an EGR gas in the combustion chamber (5) is more than the amount of the EGR gas to cause the generation amount of the soot to reach the peak and to hardly generate a soot, and a second combustion mode (II) in which the amount of the EGR gas in the combustion chamber is less than the amount of the EGR gas to cause the generation amount of the soot to reach the peak are selectively carried out. When switching from the first combustion mode (I) to the second combustion mode (II), a fuel injection start timing is delayed, and when switching from the second combustion mode (II) to the first combustion mode (I), the fuel injection start timing is advanced. <IMAGE>
