Disclosed is a combustion/temperature increase control method for an after-treatment burner system with a burner 14 arranged upstream of a particulate filter 12 (exhaust gas purification member) incorporated in an exhaust pipe 11 to increase a temperature of the exhaust gas purification member by combustion with the burner 14. For temperature increase of the particulate filter 12 to a target temperature through ignition of the burner 14, fuel injection control of the burner 14 is effected such that a temperature increase rate of the particulate filter 12 is kept relatively high till approaching to a target temperature and is lowered stepwise after approaching to the target temperature.