Lactone-containing compounds having formula (1) are novel wherein A1 is a polymerizable functional group having a double bond, R1 is a monovalent C1-C10 hydrocarbon group in which some or all hydrogen atoms are substituted by fluorine atoms, and W is CH2, O or S. They are useful as monomers to produce polymers for the formulation of radiation-sensitive resist compositions which have high transparency to radiation of up to 500 nm and exhibit good development properties. Radiation-sensitive resist compositions comprising the polymers as base resin exhibit high resolution and prevent dissolution in water and penetration of water when processed by immersion lithography.