An engine exhaust treatment device is capable of combusting PM accumulated in a DPF or activating an exhaust purification catalyst even immediately after engine startup or at the time of light load operation. A combustible gas supply passage (8) communicates with an exhaust passage (4) on an upstream of a combustion catalyst (5). An air supply unit (9) and an ignition unit (10) are provided in this supply passage and interlocked with a control unit (11). Where a temperature of the exhaust is lower than a predetermined temperature, the control unit supplies air (12) to a combustible gas by the air supply unit (9) and causes ignition of the combustible gas by the ignition unit (10), so as to cause flame combustion of the combustible gas. The temperature of the exhaust (6) in the exhaust passage (4) is increased by heat of this flame combustion.