A sulfonyloxime compound is provided which is represented by a general formula (1): wherein, R1 represents a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group; R2 represents an alkyl group, an aryl group, or a heteroaryl group; X represents a halogen atom; Y represents —R3, a —CO—R3 group, —COO—R3 group, —CONR3R4 group, —S—R3 group, —SO—R3 group, —SO2—R3 group, a —CN group or a —NO2 group, and R3 and R4 within the Y group each represent a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group, although any two of R1, R2 and R3 may also be bonded together to form a cyclic structure, and furthermore dimers of a compound represented by the general formula (1) in which R1, R2 or Y groups from separate molecules are bonded together to form a single bivalent group, are also possible. This compound is very useful as a radiation sensitive acid generator which is sensitive to activated radiation such as far ultraviolet radiation or electron beams and the like, and displays superior heat stability and storage stability. Furthermore, chemically amplified positive type or negative type radiation sensitive resin compositions incorporating such a radiation sensitive acid generator are also provided.