To obtain a peroxide having a proper plate gelling time, with shortened startup time and capable of reproducing a molded product with low odor and low residual styrene content.

The objective peroxycarbonate is suitable as a curing agent for thermosetting resins such as unsaturated polyester resins or vinyl ester resins and shown by the formula (1) [wherein, n is 1 or 2; R2 is a (1-3C lower alkoxy-substituted) 3-16C alkyl, cyclohexyl, 4-t-butylcyclohexyl or benzyl; when n is 1, R1 is a 1-6C straight-chain or branched alkyl or (1-3C alkyl-substituted) phenyl, when n is 2, R1 is ethylene group, ethynylene group or phenylene group]. The 2nd objective curing agent with the peroxycarbonate as the active ingredient, the 3rd objective resin composition containing the peroxycarbonate, and the 4th objective thermosetting resin molded form cured using the peroxycarbonate, are provided, respectively.