To obtain an aqueous emulsion excellent in emulsion stability without using an alkylphenol derivative type dispersant having a doubt of an endocrine disrupting substance and to effectively ensure adhesive capacity when the aqueous emulsion is used as a tackifier.

An emulsifying dispersant for the aqueous emulsion contains a sulfate ester salt of polyoxyalkylene rosin ester, which is obtained by adding alkylene oxide to rosins and subjecting the obtained adduct to sulfation and neutralization reaction, as an effective component. A resin emulsion obtained using this rosin ester type emulsifying dispersant is excellent in dispersibility and mechanical stability. When a rosin resin is emulsified as a tackifier resin by the emulsifying dispersant, the capacity of an aqueous adhesive is by no means inferior to a case using a conventional alkylphenol derivative.