A method for manufacturing an optical element includes pressing a phosphate-based glass containing Bi2O3 in a proportion of 10 mass % or higher and 30 mass % or lower with a hot mold; and then cooling the same, in which pressure equal to or higher than the critical pressure of oxygen and equal to or lower than a strength of glass is continuously applied to the glass from the time of bringing the glass into contact with the pressing surface of the mold at a glass viscosity of log η=9 [dPa·sec] or higher and 10 [dPa·sec] or lower until the glass viscosity log η increases to 12 [dPa·sec] by cooling.