An aluminum-halogen fuel cell comprising: a positive electrode; a negative electrode; an electrolyte comprising an ionic liquid represented by formula: in the formula, R 1 represents an unsubstituted or substituent-containing C1 to C20 alkyl group, R 2 represents a hydrogen atom, a C1 to C4 alkyl group, an alkenyl group, or a polymer repeating unit derived from the alkenyl group, each of R 3 and R 4 independently represents a hydrogen atom, a halogen atom or a C1 to C4 alkyl group, R 5 represents a hydrogen atom or a C1 to C4 alkyl group, X represents AlCl 4, AlBr 4, AlCl 3 Br or AlClBr 3, and Y represents Al 2 Cl 7, Al 2 Cl 6 Br, Al 2 Br 7 or Al 2 ClBr 6, provided that a combination of X and Y is a combination of AlCl 4 and Al 2 Cl 7, a combination of AlCl 3 Br and Al 2 Cl 6 Br, a combination of AlBr 4 and Al 2 Br 7 or a combination of AlClBr 3 and Al 2 ClBr 6, and n represents a real number of 0 to 1, by formula: in the formula, R 6 represents a hydrogen atom or an unsubstituted or substituent-containing C1 to C10 alkyl group, R 7 represents a C1 to C4 alkyl group, an alkenyl group, or a polymer repeating unit derived from the alkenyl group, k represents 0 or 1, and X, Y and n have the same meanings as X, Y and n in formula, or by formula: in the formula, A represents a nitrogen atom or a phosphorus atom, provided that when A represents a nitrogen atom, each of R 8 to R 11 independently represents a hydrogen atom or an unsubstituted or substituent-containing C1 to C10 alkyl group, and when A represents a phosphorus atom, each of R 8 to R 11 independently represents a halogen atom or an unsubstituted or substituent-containing C1 to C20 alkyl group, and X, Y and n have the same meanings as X, Y and n in formula; and a halogen gas inlet line configured to supply a halogen gas to the positive electrode. a positive electrode; a negative electrode; an electrolyte comprising an ionic liquid represented by formula: in the formula, R 1 represents an unsubstituted or substituent-containing C1 to C20 alkyl group, R 2 represents a hydrogen atom, a C1 to C4 alkyl group, an alkenyl group, or a polymer repeating unit derived from the alkenyl group, each of R 3 and R 4 independently represents a hydrogen atom, a halogen atom or a C1 to C4 alkyl group, R 5 represents a hydrogen atom or a C1 to C4 alkyl group, X represents AlCl 4, AlBr 4, AlCl 3 Br or AlClBr 3, and Y represents Al 2 Cl 7, Al 2 Cl 6 Br, Al 2 Br 7 or Al 2 ClBr 6, provided that a combination of X and Y is a combination of AlCl 4 and Al 2 Cl 7, a combination of AlCl 3 Br and Al 2 Cl 6 Br, a combination of AlBr 4 and Al 2 Br 7 or a combination of AlClBr 3 and Al 2 ClBr 6, and n represents a real number of 0 to 1, by formula: in the formula, R 6 represents a hydrogen atom or an unsubstituted or substituent-containing C1 to C10 alkyl group, R 7 represents a C1 to C4 alkyl group, an alkenyl group, or a polymer repeating unit derived from the alkenyl group, k represents 0 or 1, and X, Y and n have the same meanings as X, Y and n in formula, or by formula: in the formula, A represents a nitrogen atom or a phosphorus atom, provided that when A represents a nitrogen atom, each of R 8 to R 11 independently represents a hydrogen atom or an unsubstituted or substituent-containing C1 to C10 alkyl group, and when A represents a phosphorus atom, each of R 8 to R 11 independently represents a halogen atom or an unsubstituted or substituent-containing C1 to C20 alkyl group, and X, Y and n have the same meanings as X, Y and n in formula; and a halogen gas inlet line configured to supply a halogen gas to the positive electrode.