To provide a fluorinated compound having an RF group with at most 6 carbon atoms, whereby a fluorinated polymer having a highly durable water/oil repellency can be produced, and an environmental load is little, and a fluorinated polymer and a fluorinated copolymer having a highly durable water/oil repellency and presenting little environmental load, obtainable by polymerizing such a fluorinated compound. A fluorinated compound represented by the following formula (I) and its polymer: CH2═C(M)COO(CH2)nPhCOO(CH2)mCrF2r+1  (I) (in the formula (I), M is a hydrogen atom, a methyl group or a halogen atom, n is an integer of from 0 to 2, Ph is a phenylene group, m is an integer of from 1 to 4, and r is an integer of from 1 to 6).