Provided are an emulsifier derived from sugar polymer capable of successfully emulsifying even unsaturated oil, a production method therefore, and a production method for emulsion using the emulsifier. This emulsifier can be obtained by a production method including an emulsification improving step of improving the emulsification of sugar polymer particles dispersed in water. In this emulsification improving step, the emulsification of sugar polymer particles can be improved by an action of an emulsification aid that is at least water-soluble one kind selected from salts, an amphiphilic agent, saccharides, an organic acid, and an amino acid. Alternatively, the emulsification of sugar polymer particles can be improved by storing the sugar polymer particles dispersed in water at a low temperature of 10° C. or lower.