To obtain an internal latent image type direct positive silver halide emulsion having high sensitivity and high contrast in a low density part on its reversal characteristic curve and to obtain a color diffusion transfer photosensitive material using the silver halide emulsion.

The direct positive silver halide emulsion contains silver halide grains having a composite structure prepared in such a way that the iodine content of the silver halide of a silver halide phase formed on the surfaces of silver halide grains is made higher than that of the silver halide of the inner phase. The average iodine content of the entire grains is <1.0 mol% and the amount of iodine fed for the silver halide phase is 0.005 to <0.3 mol% of the amount of the entire grains.