Polymers comprising recurring units of an acrylic derivative of fluorinated backbone represented by formula (1) are novel. R1, R2 and R3 are independently H, F, C1-20 alkyl or fluorinated C1-20 alkyl, at least one of R1, R2 and R3 contains fluorine, and R4 is a hydrophilic group. Using the polymers, chemical amplification positive resist compositions featuring low absorption of F2 excimer laser light are obtained.