The present invention provides a difluprednate emulsion composition showing immediate effectiveness of preservative efficacy. The immediate effectiveness of preservative efficacy is achieved by adding an antimicrobial metal (excluding zinc). The present invention also provides a method of conferring immediate effectiveness of the preservative efficacy to an emulsion composition comprising difluprednate, the method includes preparing an emulsion composition comprising difluprednate and an antimicrobial metal (excluding zinc).