To provide a new compound useful as a photopolymerization initiator having high sensitivity and free from the troubles of the discoloration of polymer and contamination of polymer, apparatus, etc., and provide a photopolymerization initiator containing the compound as an active component and a photosensitive composition containing the photopolymerization initiator.

The oxime ester compound is expressed by general formula (I) (X1 is H, a halogen atom or an alkyl; R1 is R, OR, COR, SR, CONRR' or CN; R2 is R, OR, COR, SR or NRR'; R3 is R, OR, COR, SR or NRR'; R and R' are each an alkyl, an aryl, an aralkyl or a heterocyclic group; these groups may be substituted with a halogen atom and/or a heterocyclic group; the alkylene unit of the alkyl and aralkyl group may be interrupted by an unsaturated bond, an ether bond, a thioether bond or an ester bond; and R and R' may together form a ring). The photopolymerization initiator contains the compound as an active component and the photosensitive composition contains the photopolymerization initiator in a polymerizable compound having an ethylenic unsaturated bond.