There is provided a sulfonium salt having high photosensitivity to the i-line. The invention relates to a sulfonium salt represented by formula (1) described below: [in formula (1), R1 to R6 each independently represent an alkyl group, a hydroxy group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an arylthiocarbonyl group, an acyloxy group, an arylthio group, an alkylthio group, an aryl group, a heterocyclic hydrocarbon group, an aryloxy group, an alkylsulfinyl group, an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a hydroxy(poly) alkyleneoxy group, an optionally substituted amino group, a cyano group, a nitro group, or a halogen atom, m1 to m6 each represent the number of occurrences of each of R1 to R6, m1, m4, and m6 each represent an integer of 0 to 5, m2, m3, and m5 each represent an integer of 0 to 4, and X− represents a monovalent polyatomic anion].