Provided is a foamable oil-in-water emulsion that, regardless of having a low percent content of fat and total solids, has superior foamability, flower-forming properties, shape retention, sense of concentrated flavor, and lack of heavy mouthfeel. The foamable oil-in-water emulsion, which has a percent oil and fat content of 8-22 wt% and a percent content of total solids of 30-60 wt%, contains casein sodium and an emulsifier and has an overrun value in the optimal foamed state of at least 200%. The percent content of casein sodium is preferably 0.8-4.0 wt%.