A self-adhesive silicone gel composition comprising: 100 parts by weight of an organopolysiloxane having an average composition formula described below: R a R 1 b SiO (4-a-b)/2 wherein R is independently an alkenyl group, R 1 is independently an unsubstituted or substituted monovalent hydrocarbon group free of an aliphatic unsaturated bond, a is a positive number of 0.0001 to 0.2, b is a positive number of 1.7 to 2.2, and a + b is a positive number of 1.9 to 2.4, the organopolysiloxane having at least one alkenyl group bonded to a silicon atom in one molecule; 20 to 200 parts by weight of an organopolysiloxane having an average composition formula described below: R 1 c SiO (4-c)/2 wherein R 1 is equal to R 1 in component, and c is a positive number of 1.9 to 2.4; an organohydrogenpolysiloxane having an average composition formula described below: R 2 d H e SiO (4-d-e)/2 wherein R 2 is independently an unsubstituted or substituted monovalent hydrocarbon group free of an aliphatic unsaturated bond, d is a positive number of 0.7 to 2.2, e is a positive number of 0.001 to 1, and d + e is a positive number of 0.8 to 3, the organohydrogenpolysiloxane having at least two hydrogen atoms each bonded to a silicon atom in one molecule, in such an amount that 0.01 to 3 hydrogen atoms are bonded to a silicon atom in component per one alkenyl group bonded to a silicon atom in a whole of the self-adhesive silicone gel composition; an effective amount of a platinum group metal-based catalyst; 0.1 to 30 parts by weight of a partial hydrolytic condensate of a hydrolyzable silane having a general formula described below: Si(OR 3) 4 wherein R 3 is independently an aliphatic monovalent hydrocarbon group having 1 to 10 carbon atoms, the partial hydrolytic condensate as a whole having a residual ratio of the hydrolyzable silane having the general formula of 1.0 mol% or less, the partial hydrolytic condensate included at a content of 99.0 mol% or more; and a metal carboxylate in an amount of 1 to 1,000 ppm based on a weight of the whole of the self-adhesive silicone gel composition, the metal carboxylate having a general formula described below: (R 4 COO) f M wherein R 4 is an identical or nonidentical monovalent hydrocarbon group, M is a metal atom selected from cerium, iron, nickel, and niobium, f is 3 or 4 in a case where M is cerium or iron, 2 in a case where M is nickel, and 4 or 5 in a case where M is niobium, the self-adhesive silicone gel composition free of a hydrolyzable silane other than component. 100 parts by weight of an organopolysiloxane having an average composition formula described below: R a R 1 b SiO (4-a-b)/2 wherein R is independently an alkenyl group, R 1 is independently an unsubstituted or substituted monovalent hydrocarbon group free of an aliphatic unsaturated bond, a is a positive number of 0.0001 to 0.2, b is a positive number of 1.7 to 2.2, and a + b is a positive number of 1.9 to 2.4, the organopolysiloxane having at least one alkenyl group bonded to a silicon atom in one molecule; 20 to 200 parts by weight of an organopolysiloxane having an average composition formula described below: R 1 c SiO (4-c)/2 wherein R 1 is equal to R 1 in component, and c is a positive number of 1.9 to 2.4; an organohydrogenpolysiloxane having an average composition formula described below: R 2 d H e SiO (4-d-e)/2 wherein R 2 is independently an unsubstituted or substituted monovalent hydrocarbon group free of an aliphatic unsaturated bond, d is a positive number of 0.7 to 2.2, e is a positive number of 0.001 to 1, and d + e is a positive number of 0.8 to 3, the organohydrogenpolysiloxane having at least two hydrogen atoms each bonded to a silicon atom in one molecule, in such an amount that 0.01 to 3 hydrogen atoms are bonded to a silicon atom in component per one alkenyl group bonded to a silicon atom in a whole of the self-adhesive silicone gel composition; an effective amount of a platinum group metal-based catalyst; 0.1 to 30 parts by weight of a partial hydrolytic condensate of a hydrolyzable silane having a general formula described below: Si(OR 3) 4 wherein R 3 is independently an aliphatic monovalent hydrocarbon group having 1 to 10 carbon atoms, the partial hydrolytic condensate as a whole having a residual ratio of the hydrolyzable silane having the general formula of 1.0 mol% or less, the partial hydrolytic condensate included at a content of 99.0 mol% or more; and a metal carboxylate in an amount of 1 to 1,000 ppm based on a weight of the whole of the self-adhesive silicone gel composition, the metal carboxylate having a general formula described below: (R 4 COO) f M wherein R 4 is an identical or nonidentical monovalent hydrocarbon group, M is a metal atom selected from cerium, iron, nickel, and niobium, f is 3 or 4 in a case where M is cerium or iron, 2 in a case where M is nickel, and 4 or 5 in a case where M is niobium, the self-adhesive silicone gel composition free of a hydrolyzable silane other than component.