An object of the present invention is to provide a novel monomer compound having a lactone structure which gives polymers having more excellent feature as resist material, etc. The present invention relates to a compound represented by the following formula [1]: wherein R1 and R2 are an alkyl group; R3 and R4 are each independently hydrogen atom or an alkyl group; R5 is hydrogen atom, acryloyl group or methacryloyl group; and X is a methylene group which may have an alkyl group or an ethylene group which may have an alkyl group. The present invention provides a compound having a lactone structure which gives a polymer having more excellent feature particularly as a resist material and also provides a hydroxy lactone being useful as a material, etc. therefor.