Plant sterol is stably dispersed in a water-based food product or emulsified food product without detracting from the flavor of the food product. A complex of plant sterol and egg yolk lipoprotein is provided. This complex can be obtained by stirring and mixing egg yolk liquid and plant sterol (preferably 185 parts by mass or less of plant sterol per 1 part by mass of egg yolk solids) in a water-based medium. This complex can be used in food products as a liquid dispersion or can be used as a dried powder.