A room-temperature-curable composition comprising: (a) 100 parts by weight of polyoxyalkylene compound having a main chain of polyoxyalkylene polymer and having per molecule at least one reactive silicon group represented by the following structural formula at a molecular chain terminal: wherein R 1 and R 2 may be the same or different, and each represents an unsubstituted or substituted monovalent hydrocarbon group having 1 to 20 carbon atoms, a hydrogen atom, or a triorganosiloxy group represented by (R 3) 3 Si-O- where R 3 represents a monovalent hydrocarbon group having 1 to 20 carbon atoms, and the three R 3 s may be the same or different, n represents an integer of 2 or more, m represents 4, and the broken line represents a linking bond; (b) 0.1 to 30 parts by weight of the following component (b-1) and/or component (b-2): (b-1) hydrolysable organosilicon compound having two alkoxysilyl-vinylene groups on the same silicon atom, represented by the following general formula, and/or a partial hydrolytic condensate thereof: wherein R 5 independently represents an unsubstituted or substituted monovalent hydrocarbon group having 1 to 20 carbon atoms, R 6 represents an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms, or an unsubstituted or substituted cycloalkyl group having 3 to 20 carbon atoms, and a represents an integer of 1 to 3; (b-2) hydrolysable organosilane free of amino group, having one methyl group, one vinyl group, or one phenyl group, and having at least two hydrolysable groups in the molecule thereof, and being other than component (b-1), and/or a partial hydrolytic condensate thereof; and (c) 0.01 to 20 parts by weight of curing catalyst. (a) 100 parts by weight of polyoxyalkylene compound having a main chain of polyoxyalkylene polymer and having per molecule at least one reactive silicon group represented by the following structural formula at a molecular chain terminal: wherein R 1 and R 2 may be the same or different, and each represents an unsubstituted or substituted monovalent hydrocarbon group having 1 to 20 carbon atoms, a hydrogen atom, or a triorganosiloxy group represented by (R 3) 3 Si-O- where R 3 represents a monovalent hydrocarbon group having 1 to 20 carbon atoms, and the three R 3 s may be the same or different, n represents an integer of 2 or more, m represents 4, and the broken line represents a linking bond; (b) 0.1 to 30 parts by weight of the following component (b-1) and/or component (b-2): (b-1) hydrolysable organosilicon compound having two alkoxysilyl-vinylene groups on the same silicon atom, represented by the following general formula, and/or a partial hydrolytic condensate thereof: wherein R 5 independently represents an unsubstituted or substituted monovalent hydrocarbon group having 1 to 20 carbon atoms, R 6 represents an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms, or an unsubstituted or substituted cycloalkyl group having 3 to 20 carbon atoms, and a represents an integer of 1 to 3; (b-2) hydrolysable organosilane free of amino group, having one methyl group, one vinyl group, or one phenyl group, and having at least two hydrolysable groups in the molecule thereof, and being other than component (b-1), and/or a partial hydrolytic condensate thereof; and (b-1) hydrolysable organosilicon compound having two alkoxysilyl-vinylene groups on the same silicon atom, represented by the following general formula, and/or a partial hydrolytic condensate thereof: wherein R 5 independently represents an unsubstituted or substituted monovalent hydrocarbon group having 1 to 20 carbon atoms, R 6 represents an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms, or an unsubstituted or substituted cycloalkyl group having 3 to 20 carbon atoms, and a represents an integer of 1 to 3; (b-2) hydrolysable organosilane free of amino group, having one methyl group, one vinyl group, or one phenyl group, and having at least two hydrolysable groups in the molecule thereof, and being other than component (b-1), and/or a partial hydrolytic condensate thereof; and (c) 0.01 to 20 parts by weight of curing catalyst.