To provide a free-radically curable resin composition which can be stored for a long time, is excellent in curing rate, and gives a cured item excellent in physical properties; and its curing method and production method.

This resin composition contains (A) a free-radically curable resin, (B) an N-vinyl compound represented by formula (1) (R1 to R7 are each H or an organic group), and (C) an N-oxyl compound derivative represented by formula (2) (R8 and R9 are each H or an organic group; R10 to R14 are each H or an alkyl; and m is an integer of 1 of higher). The curing method comprises curing the resin composition with an active energy ray.