The major features of the stratified charge engine with an auxiliary chamber are: (1) the mixture in the combustion chamber has concentration gradient due to the auxiliary chamber and (2) turbulent flame is injected into the main chamber. The objective of this research is to examine those effects upon the combustion characteristics and the burned gas composition. The characteristics of flame propagation were examined by using a series of schlieren photographs.A summary of the major conclusion of this research is given below:(1) The mixtures supplied in the main and the auxiliary chambers burn without mixing with each other.(2) The concentrations of HC and CO decrease as the closer the mixture in the auxiliary chamber approaches stoichiometry and the leaner the mixture in the main chamber. The concentration of CO decreases as the torch opening area decreases.(3) The concentration of NOx decreases as the mixture in the auxiliary chamber becomes richer, the mixture in the main chamber becomes leaner and the torch opening area becomes larger.