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The compound capable of generating an organic acid rep› resented by formula (I) upon irradiation with an actinic ray or radiation is preferably a sulfonium salt compound of the organic acid represented by formula (I), or an iodonium salt compound of the organic acid represented by formula (I), more preferably a compound represented by the following formula (Al) or (A2): 

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In formula (Al), each ofR$_{20}$ i, R$_{202 }$and R$_{203 }$independently represents an organic group. 

x- represents a sulfonate anion where the hydrogen atom in the -SO$_{3}$H moiety of the organic acid represented by formula (I) is deprived of. 

The carbon number of the organic group as R$_{20}$ i, R$_{202 }$and R$_{203 }$is generally from 1 to 30, preferably from 1 to 20. 

Two members out ofR$_{201 }$to R$_{203 }$may combine to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amido bond or a carbonyl group. Examples of the group formed by combining two members out ofR$_{201 }$to R$_{203 }$include an alkylene group ( e.g., buty lene, penty lene). 

Specific examples of the organic group as R$_{201}$, R$_{202 }$and R$_{203 }$ include the corresponding groups in the compounds (Al a), (Alb) and (Al c) described later. 

The compound may be a compound having a plurality of structures represented by formula (Al). For example, the compound may be a compound having a structure where at least one of R$_{201 }$ to R$_{203 }$ in the compound represented by formula (Al) is bonded to at least one of R$_{201 }$ to R$_{203 }$ in another compound represented by formula (Al). 

15 The component (Al) is more preferably a compound (Ala), (Alb) or (Ale) described below. 

The compound (Ala) is an arylsulfonium compound where at least one ofR$_{201 }$to R$_{203 }$in formula (Al) is an aryl group, that is, a compound having arylsulfonium as the cat- 10n. 

In the arylsulfonium compound, R$_{201 }$to R$_{203 }$all may be an aryl group or a part ofR$_{201 }$to R$_{203 }$may be an aryl group, with the remaining being an alkyl group or a cycloalkyl group. 

Examples of the arylsulfonium compound include a triar› ylsulfonium compound, a diarylalkylsulfonium compound, a diarylcycloalkylsulfonium compound, an aryldialkylsulfo› nium compound, an aryldicycloalkylsulfonium compound and an arylalkylcycloalkylsulfonium compound. 

The aryl group in the arylsulfonium compound is prefer› ably a phenyl group or a naphthyl group, more preferably a phenyl group. In the case where the arylsulfonium compound has two or more aryl groups, these two or more aryl groups may be the same or different. 

The alkyl group which is present, if desired, in the arylsul› fonium compound is preferably a linear or branched alkyl group having a carbon number of 1 to 15, and examples thereof include a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group and a tert-butyl group. 

The cycloalkyl group which is present, if desired, in the arylsulfonium compound is preferably a cycloalkyl group having a carbon number of 3 to 15, and examples thereof include a cyclopropyl group, a cyclobutyl group and a cyclo› hexyl group. 

The aryl group, alkyl group and cycloalkyl group ofR$_{201 }$to R$_{203 }$ each may have, as the substituent, an alkyl group (for example, an alkyl group having a carbon number of 1 to 15), a cycloalkyl group (for example, a cycloalkyl group having a carbon number of3 to 15), an aryl group (for example, an aryl group having a carbon number of 6 to 14), an alkoxy group (for example, an alkoxy group having a carbon numberofl to 15), a halogen atom, a hydroxyl group or a phenylthio group. The substituent is preferably a linear or branched alkyl group having a carbon numberof 1 to 12, a cycloalky 1 group having a carbon number of 3 to 12, or a linear, branched or cyclic alkoxy group having a carbon number of 1 to 12, and most preferably an alkyl group having a carbon number of 1 to 4, or an alkoxy group having a carbon number of 1 to 4. The substituent may be substituted to any one of three members R$_{201 }$to R$_{203 }$or may be substituted to all of these three mem- bers. In the case where R$_{201 }$ to R$_{203 }$ are an aryl group, the substituent is preferably substituted at the p-position of the aryl group. 

The compound (Alb) is described below. 

The compound (Alb) is a compound when each ofR$_{201 }$to R$_{203 }$ in formula (Al) independently represents an organic 

