A polymer comprising recurring units of formula (1-1) or (1-2) wherein R1, R2, R3 and R4 are H or C1-15 alkyl, R1 and R2, and R3 and R4, taken together, may form a ring; R5 and R6 are H, C1-15 alkyl, acyl or alkylsulfonyl groups or C2-15 alkoxycarbonyl or alkoxyalkyl groups which may have halogen substituents; and k=0 or 1, and having a Mw of 1,000-500,000 is novel. A resist composition comprising the polymer as a base resin is sensitive to high-energy radiation, has excellent sensitivity, resolution, etching resistance, and minimized swell and lends itself to micropatterning with electron beams or deep-UV.