A conventional polymerization inhibitor is for example an agent to scavenge radicals generated during storage of a radical polymerizable compound and used to stably handle the radical polymerizable compound, but is unnecessary when the radical polymerizable compound is to be subjected to radical polymerization reaction, and is preferably removed at the time of the radical polymerization reaction. The object of the present invention is to obviate inconvenience of removing the polymerization inhibitor at the time of radical polymerization.
The radical polymerization control agent contained in a radical polymerizable composition of the present invention functions as a radical polymerization inhibitor for example stored in a dark place, but loses its radical polymerization inhibiting effect when polymerization is initiated while being irradiated with light at a certain specific wavelength at the time of polymerization. Thus, radical polymerization of the radical polymerizable compound is easily initiated without increasing the amount of a radical polymerization initiator. That is, the radical polymerization control agent of the present invention is a radical polymerization control agent which is a corn pound having an effect to inhibit radical polymerization of a radical polymerizable compound and which loses the radical polymerization inhibiting effect under irradiation with light rays containing light within a wavelength range of from 300 nm to 500 nm.