To obtain the subject copolymer capable of providing a coating membrane excellent in chemical resistance, soil-removal properties, resistance to striped soil by rain, etc., and further providing excellent preservation stability and readily drying properties to the coated material when being used as a powdered coating material.

This fluorine based copolymer comprises (A) a polymer unit based on a fluoroolefin, (B) a polymer unit based on a cyclic monomer having an unsaturated group copolymerizable with the fluoroolefin in a ring, (C) a polymer unit based on ethylenically unsaturated compound having neither an ester bond nor an ether bond having hardenable portions and optionally (D) a polymer unit based on one or more kinds of olefins selected from ethylene, propylene and isobutylene. The proportions of each components A to D based on the total of the components A to D is regulated so as to be 35-65mol% component A, 5-45mol% component B, 1-30mol% component C and 0-40mol% component D. Further, the fluorine-based copolymer has 2,000-100,000 number- average molecular weight, and has rings in the main chain based on the above cyclic monomer.