To obtain a photopolymerizable composition having high sensitivity even to light in the UV region of >1,000 nm.

The photopolymerizable composition contains (A) an ethylenic unsaturated compound, (B-1) an N,N-diaryliminium cation which is asymmetric in one of molecular minor and major axes in the chemical structural formula and (B-2) an organic boron anion, or (B) the salt of an N,N-diaryliminium cation which is asymmetric in one of molecular minor and major axes in the chemical structural formula and a counter anion other than an organic boron anion, and (C) a photopolymerization initiator.