In particular, a composition for breast augmentation that includes a composition promoting an increase in subcutaneous tissue, wherein the promoting composition aims at accumulating and increasing adipose tissue under the skin of a breast by generating and increasing the adipose tissue around a mammary gland and enables recovery of autologous tissue and recovery of appearance by a safe and natural process, and a method for breast augmentation are provided. A composition promoting an increase in subcutaneous tissue that contains autologous plasma and a basic fibroblast growth factor (b-FGF), in particular, a composition for breast augmentation is provided. A composition for breast augmentation that includes the above-described composition promoting an increase in subcutaneous tissue that further contains fat is provided. Specifically, a composition for breast augmentation that includes the above-described composition promoting an increase in subcutaneous tissue, wherein the fat is in the form of a lipid emulsion and the lipid emulsion is an oil-in-water lipid emulsion produced by emulsifying fat and oil in the presence of an emulsifier, and a method for breast augmentation by using the composition are provided. An injection unit of the composition for breast augmentation is also provided.