As such acid generators especially preferable in the present invention, there can be exemplified by compounds represented by the following formulae [11], [12], [14], [15], [16] and [18]: wherein R9 and R10 are independently an alkyl group or a haloalkyl group; and A??? is a sulfonyl group or a carbonyl group. wherein R11 is a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or a halo