Fuel injection apparatus of diesel engine

In a diesel engine which executes main injection near a top dead center of a compression stroke and executes post injection in an expansion stroke, the post injection is executed at a main injection combustion end timing, that is, at a timing in which heat generating rate due to a combustion of the main injection fuel is substantially 0 or less, whereby generating amounts of HC and soot are reduced. Further, at a cold time or in a cold state, a fuel injection amount in accordance with the post injection is increased rather than a normal time or in a warm state, whereby a warming-up of the engine or a temperature increase and activation of an exhaust gas purifying catalyst is promoted.