PROBLEM TO BE SOLVED: To provide a method for efficiently performing lycopene cis-isomerization without using a catalyst such as iodine.SOLUTION: In one embodiment, a lycopene cis-isomerization method is provided in which a lycopene solution obtained by dissolving a lycopene into a solvent comprising ethyl acetate, acetone or hexane, is irradiated with light within the range of 300 to 500 nm. In another embodiment, a lycopene cis-isomerization method is provided as an alternative to the above lycopene cis-isomerization method, in which the irradiation duration time is 10 minutes to 30 hours. In further another embodiment, a lycopene cis-isomerization method is provided as an alternative to any one of the above lycopene cis-isomerization methods, in which the lycopene solution is a solution obtained by dissolving an oleoresin prepared from fruits and vegetables into the solvent. A method for producing food and beverage is provided in which the lycopene that is cis-isomerized by any one of the above lycopene cis-isomerization methods is used as a raw material, and a method for producing cosmetic is also provided in which the lycopene that is cis-isomerized by any one of the above lycopene cis-isomerization methods is used as a raw material.
