Homogeneous charge compression ignition combustion is auto ignition of homogeneous intake gas. But in the HCCI engine, there are inhomogeneity of fuel distribution, temperature, and gas composition that are produced by residual gas, flow, and heat transfer on the wall. In this study, the effect of fuel distribution in the intake gas was investigated with Rapid Compression Machine. In the result, inhomogeneity of fuel distribution caused spatial and temporal dispersion of luminescence. And in the condition of nonexistence of residual gas and flow, overall luminescence intensity was same.