The present invention provides: a self-emulsifying composition comprising, relative to 100 parts by weight of a solid preparation, 0.1-0.5 parts by weight of dutasteride, 6-110 parts by weight of oil, and 6-110 parts by weight of a surfactant; a solid preparation comprising 5-185 parts by weight of a coating excipient comprising pores formed in a surface thereof, the self-emulsifying composition being accommodated in the pores; and a method for preparing the solid preparation.