A 3,5-disubstituted benzene alkynyl compound or a salt thereof for use in a treatment of a tumor patient resistant to at least one FGFR inhibitor selected from the group consisting of ponatinib, regorafenib, intedanib, dovitinib lactate, lenvatinib mesylate, cediranib, oratinib, brivanib alaninate, AZD4547, NVP-BGJ398, sulfatinib, ARQ-087, S-49076, IMCA1, PROO01, and R3Mab, the 3,5-disubstituted benzene alkynyl compound being represented by Formula (I): wherein R 1 is the same or different, and each represents C 1 -C 6 alkyl; X 1 and X 2 independently represent N or CH; Y is a group represented by Formula (A): wherein the divalent moiety represented by is a nitrogen-containing C 3 -C 10 heterocycloalkylene group, a group represented by Formula (B): wherein the divalent moiety represented by is a C 3 -C 10 cycloalkylene group, or a group represented by Formula (C): wherein the divalent moiety represented by is a C 6 -C 12 arylene group; R 2 is hydrogen, C 2 -C 6 alkynyl, -C(=O)OR x , -C(=O)N(R x )(R y ), hydroxy-C 1 -C 6 alkyl, di (C 1 -C 6 alkyl)amino-C 1 -C 6 alkyl, or C 2 -C 9 heteroaryl optionally having R 3 ; and R 3 is C 1 -C 6 alkyl or di(C 1 -C 6 alkyl) amino-C 1 -C 6 alkyl; Z is -C(R 4 ) =C(R 5 )(R 6 ) or -C≡C-R 7 ; R 4 , R 5 , and R 6 are the same or different, and each represents hydrogen, halogen, C 1 -C 6 alkyl optionally having R 8 , or a group represented by Formula (D): wherein the monovalent moiety represented by is a nitrogen-containing C 3 -C 10 heterocycloalkyl group, R 7 is hydrogen, C 1 -C 6 alkyl, or hydroxy-C 1 -C 6 alkyl; R 8 is -OR x or -N(R x )(R y ) ; R 9 is C 1 -C 6 alkyl, halogen, or -OR x ; R x and R y are the same or different, and each represents hydrogen, C 1 -C 6 alkyl, C 3 -C 10 cycloalkyl, di (C 1 -C 6 alkyl) amino-C 1 -C 6 alkyl, or C 1 -C 6 alkoxy-C 1 -C 6 alkyl; l is an integer of 0 to 3; m is an integer of 1 to 3; and n is an integer of 0 to 2. wherein R 1 is the same or different, and each represents C 1 -C 6 alkyl; X 1 and X 2 independently represent N or CH; Y is a group represented by Formula (A): wherein the divalent moiety represented by is a nitrogen-containing C 3 -C 10 heterocycloalkylene group, a group represented by Formula (B): wherein the divalent moiety represented by is a C 3 -C 10 cycloalkylene group, or a group represented by Formula (C): wherein the divalent moiety represented by is a C 6 -C 12 arylene group; R 2 is hydrogen, C 2 -C 6 alkynyl, -C(=O)OR x , -C(=O)N(R x )(R y ), hydroxy-C 1 -C 6 alkyl, di (C 1 -C 6 alkyl)amino-C 1 -C 6 alkyl, or C 2 -C 9 heteroaryl optionally having R 3 ; and R 3 is C 1 -C 6 alkyl or di(C 1 -C 6 alkyl) amino-C 1 -C 6 alkyl; Z is -C(R 4 ) =C(R 5 )(R 6 ) or -C≡C-R 7 ; R 4 , R 5 , and R 6 are the same or different, and each represents hydrogen, halogen, C 1 -C 6 alkyl optionally having R 8 , or a group represented by Formula (D): wherein the monovalent moiety represented by is a nitrogen-containing C 3 -C 10 heterocycloalkyl group, R 7 is hydrogen, C 1 -C 6 alkyl, or hydroxy-C 1 -C 6 alkyl; R 8 is -OR x or -N(R x )(R y ) ; R 9 is C 1 -C 6 alkyl, halogen, or -OR x ; R x and R y are the same or different, and each represents hydrogen, C 1 -C 6 alkyl, C 3 -C 10 cycloalkyl, di (C 1 -C 6 alkyl) amino-C 1 -C 6 alkyl, or C 1 -C 6 alkoxy-C 1 -C 6 alkyl; l is an integer of 0 to 3; m is an integer of 1 to 3; and n is an integer of 0 to 2. R 7 is hydrogen, C 1 -C 6 alkyl, or hydroxy-C 1 -C 6 alkyl; R 8 is -OR x or -N(R x )(R y ) ; R 9 is C 1 -C 6 alkyl, halogen, or -OR x ; R x and R y are the same or different, and each represents hydrogen, C 1 -C 6 alkyl, C 3 -C 10 cycloalkyl, di (C 1 -C 6 alkyl) amino-C 1 -C 6 alkyl, or C 1 -C 6 alkoxy-C 1 -C 6 alkyl; l is an integer of 0 to 3; m is an integer of 1 to 3; and n is an integer of 0 to 2. <EOS>