Disclosed are: an oxidizing liquid for chemiluminescence, which has a high flash point in comparison to conventional oxidizing liquids and is excellently safe, while maintaining chemiluminescent properties; and a chemiluminescence system. Specifically disclosed is an oxidizing liquid for chemiluminescence, which contains hydrogen peroxide and a solvent and produces a chemiluminescence phenomenon when mixed with a fluorescent liquid that contains an oxalic acid ester and a fluorescent substance. The oxidizing liquid for chemiluminescence is characterized by having a flash point of 60 DEG C or more and containing a solvent that is a mixture of at least two substances other than phthalic acid compounds. Also specifically disclosed is a chemiluminescence system which contains the oxidizing liquid and a fluorescent liquid.