An exhaust gas purifier for a diesel engine is positioned in the middle of an inlet system (3) for supplying air to a combustion chamber (2). The exhaust gas purifier comprises an HC (hydrocarbon) supply means (6), and a catalytic converter (18), which is activated by the hydrocarbon as a reduction agent to crack NOx (oxides of nitrogen) in the exhaust gas, thereby purifying the exhaust gas. <IMAGE>
