A method of producing a saccharide having a sulfate group, comprising: (a) a step of preparing a "first saccharide having a non-protected sulfate group" and a "second saccharide having a non-protected sulfate group" and (b) a step of condensing the first saccharide and the second saccharide prepared in the step (a) with each other in the presence of an acid, wherein the first saccharide and the second saccharide are represented by the following formula: wherein L is a leaving group; A is selected from the group consisting of a hydrogen atom, a protected or non-protected carboxyl group, a protected or non-protected amide group, and - CH 2 -R 4; R 1 to R 4 are each independently selected from the group consisting of a hydrogen atom, a non-protected sulfate group, a non-protected phosphate group, a protected or non-protected hydroxy group, a protected or non-protected amino group, a protected or non-protected thiol group, and a saccharide residue; at least one of R 1 to R 4 is a non-protected sulfate group; and at least one of R 1 to R 4 is a nucleophilic group selected from a hydroxy group, an amino group, and a thiol group, wherein the acid is selected from the group consisting of boron trifluoride diethyl ether (BF3-OEt2), dimethyl(methylthio)sulfonium trifluoromethanesulfonate (DMTST), trimethylsilyl trifluoromethanesulfonate, triethylsilyl trifluoromethanesulfonate, tripropylsilyl trifluoromethanesulfonate, dimethylethylsilyl trifluoromethanesulfonate, tribenzylsilyl trifluoromethanesulfonate, trinaphthylsilyl trifluoromethanesulfonate, tribenzylmethylsilyl trifluoromethanesulfonate, silver trifluoromethanesulfonate, cyclopentadienyl hafnium chloride, cyclopentadienyl zirconium chloride, a Lewis acid or tin chloride, formic acid, acetic acid, trifluoroacetic acid, trifluoroacetic anhydride, trifluoromethanesulfonic acid, and tetrafluoromethanesulfonic acid, and wherein the leaving group is selected from the group consisting of a halogen atom, a substituted or unsubstituted -O-alkyl group, a substituted or unsubstituted -O-alkenyl group, a substituted or unsubstituted -O-alkynyl group, a substituted or unsubstituted -O-aryl group, a substituted or unsubstituted -O-heteroaryl group, a substituted or unsubstituted -S-alkyl group, a substituted or unsubstituted -S-alkenyl group, a substituted or unsubstituted -S-alkynyl group, a substituted or unsubstituted -S-aryl group, and a substituted or unsubstituted -S-heteroaryl group. (a) a step of preparing a "first saccharide having a non-protected sulfate group" and a "second saccharide having a non-protected sulfate group" and (b) a step of condensing the first saccharide and the second saccharide prepared in the step (a) with each other in the presence of an acid, L is a leaving group; A is selected from the group consisting of a hydrogen atom, a protected or non-protected carboxyl group, a protected or non-protected amide group, and - CH 2 -R 4; R 1 to R 4 are each independently selected from the group consisting of a hydrogen atom, a non-protected sulfate group, a non-protected phosphate group, a protected or non-protected hydroxy group, a protected or non-protected amino group, a protected or non-protected thiol group, and a saccharide residue; at least one of R 1 to R 4 is a non-protected sulfate group; and at least one of R 1 to R 4 is a nucleophilic group selected from a hydroxy group, an amino group, and a thiol group, wherein the acid is selected from the group consisting of boron trifluoride diethyl ether (BF3-OEt2), dimethyl(methylthio)sulfonium trifluoromethanesulfonate (DMTST), trimethylsilyl trifluoromethanesulfonate, triethylsilyl trifluoromethanesulfonate, tripropylsilyl trifluoromethanesulfonate, dimethylethylsilyl trifluoromethanesulfonate, tribenzylsilyl trifluoromethanesulfonate, trinaphthylsilyl trifluoromethanesulfonate, tribenzylmethylsilyl trifluoromethanesulfonate, silver trifluoromethanesulfonate, cyclopentadienyl hafnium chloride, cyclopentadienyl zirconium chloride, a Lewis acid or tin chloride, formic acid, acetic acid, trifluoroacetic acid, trifluoroacetic anhydride, trifluoromethanesulfonic acid, and tetrafluoromethanesulfonic acid, and wherein the leaving group is selected from the group consisting of a halogen atom, a substituted or unsubstituted -O-alkyl group, a substituted or unsubstituted -O-alkenyl group, a substituted or unsubstituted -O-alkynyl group, a substituted or unsubstituted -O-aryl group, a substituted or unsubstituted -O-heteroaryl group, a substituted or unsubstituted -S-alkyl group, a substituted or unsubstituted -S-alkenyl group, a substituted or unsubstituted -S-alkynyl group, a substituted or unsubstituted -S-aryl group, and a substituted or unsubstituted -S-heteroaryl group.