A fluorine-containing diblock copolymer produced by either the following process or the following process: process a production process comprising [first step] a step of polymerizing a fluorine-containing (meth) acrylic ester represented by the following formula in the presence of a trithiocarbonic ester compound and a radical polymerization initiator to give a polymer of the fluorine-containing (meth)acrylic ester, and [second step] a step of polymerizing a non-fluorine vinyl-based monomer in the presence of the polymer of the fluorine-containing (meth) acrylic ester obtained in the first step to give a fluorine-containing diblock copolymer; process a production process comprising [first step] a step of polymerizing a non-fluorine vinyl-basedmonomer in the presence of a trithiocarbonic ester compound and a radical polymerization initiator to give a polymer of the non-fluorine vinyl-based monomer, and [second step] a step of polymerizing a fluorine-containing (meth) acrylic ester represented by the following formula in the presence of the polymer of the non-fluorine vinyl-based monomer obtained in the first step to give a fluorine-containing diblock copolymer; wherein R 1 is a hydrogen atom or a methyl group, a is an integer of 1 to 3, b is an integer of 1 to 2, n is an integer of 1 to 6, -C n F 2n+1 group is bonded to CH 2 group of-(CF 2 CH 2) b - group, and - (CF 2 CF 2) a - group is bonded to CF 2 group of -(CF 2 CH 2) b - group. process a production process comprising [first step] a step of polymerizing a fluorine-containing (meth) acrylic ester represented by the following formula in the presence of a trithiocarbonic ester compound and a radical polymerization initiator to give a polymer of the fluorine-containing (meth)acrylic ester, and [second step] a step of polymerizing a non-fluorine vinyl-based monomer in the presence of the polymer of the fluorine-containing (meth) acrylic ester obtained in the first step to give a fluorine-containing diblock copolymer; [first step] a step of polymerizing a fluorine-containing (meth) acrylic ester represented by the following formula in the presence of a trithiocarbonic ester compound and a radical polymerization initiator to give a polymer of the fluorine-containing (meth)acrylic ester, and [second step] a step of polymerizing a non-fluorine vinyl-based monomer in the presence of the polymer of the fluorine-containing (meth) acrylic ester obtained in the first step to give a fluorine-containing diblock copolymer; process a production process comprising [first step] a step of polymerizing a non-fluorine vinyl-basedmonomer in the presence of a trithiocarbonic ester compound and a radical polymerization initiator to give a polymer of the non-fluorine vinyl-based monomer, and [second step] a step of polymerizing a fluorine-containing (meth) acrylic ester represented by the following formula in the presence of the polymer of the non-fluorine vinyl-based monomer obtained in the first step to give a fluorine-containing diblock copolymer; wherein R 1 is a hydrogen atom or a methyl group, a is an integer of 1 to 3, b is an integer of 1 to 2, n is an integer of 1 to 6, -C n F 2n+1 group is bonded to CH 2 group of-(CF 2 CH 2) b - group, and - (CF 2 CF 2) a - group is bonded to CF 2 group of -(CF 2 CH 2) b - group. [first step] a step of polymerizing a non-fluorine vinyl-basedmonomer in the presence of a trithiocarbonic ester compound and a radical polymerization initiator to give a polymer of the non-fluorine vinyl-based monomer, and [second step] a step of polymerizing a fluorine-containing (meth) acrylic ester represented by the following formula in the presence of the polymer of the non-fluorine vinyl-based monomer obtained in the first step to give a fluorine-containing diblock copolymer; wherein R 1 is a hydrogen atom or a methyl group,