A methacrylic resin composition comprising an acrylic graft copolymer containing an acrylic acid ester-based rubbery polymer (A-a), wherein: the acrylic graft copolymer is obtained by polymerizing a monomer mixture (A-b), which contains a methacrylic acid ester as a major component, with the acrylic acid ester-based rubbery polymer (A-a); the acrylic acid ester-based rubbery polymer (A-a) is obtained by polymerizing a monomer mixture containing 60 to 100 wt% of an acrylic acid ester and 0 to 40 wt% of another copolymerizable vinyl-based monomer with a copolymerizable cross-linking agent; a content of the acrylic acid ester-based rubbery polymer (A-a) is 10 to 40 wt%, with respect to 100 wt% of the methacrylic resin composition; a mean particle diameter d of the acrylic acid ester-based rubbery polymer (A-a) is 50 to 200 nm; a relationship between the mean particle diameter d (nm) of the acrylic acid ester-based rubbery polymer (A-a) and the cross-linking agent content w (wt%) in a monomer mixture used in the acrylic acid ester-based rubbery polymer (A-a) satisfies an inequation of 0.02d ≤ w ≤ 0.05d; a graft ratio of the acrylic graft copolymer is 60 to 105 %; and a reduced viscosity of components of the methacrylic resin composition, the components being soluble in methyl ethyl ketone, is 0.8 to 1.3 dl/g, wherein the graft ratio and the reduced viscosity are measured as described in the description. the acrylic graft copolymer is obtained by polymerizing a monomer mixture (A-b), which contains a methacrylic acid ester as a major component, with the acrylic acid ester-based rubbery polymer (A-a); the acrylic acid ester-based rubbery polymer (A-a) is obtained by polymerizing a monomer mixture containing 60 to 100 wt% of an acrylic acid ester and 0 to 40 wt% of another copolymerizable vinyl-based monomer with a copolymerizable cross-linking agent; a content of the acrylic acid ester-based rubbery polymer (A-a) is 10 to 40 wt%, with respect to 100 wt% of the methacrylic resin composition; a mean particle diameter d of the acrylic acid ester-based rubbery polymer (A-a) is 50 to 200 nm; a relationship between the mean particle diameter d (nm) of the acrylic acid ester-based rubbery polymer (A-a) and the cross-linking agent content w (wt%) in a monomer mixture used in the acrylic acid ester-based rubbery polymer (A-a) satisfies an inequation of 0.02d ≤ w ≤ 0.05d; a graft ratio of the acrylic graft copolymer is 60 to 105 %; and a reduced viscosity of components of the methacrylic resin composition, the components being soluble in methyl ethyl ketone, is 0.8 to 1.3 dl/g, wherein the graft ratio and the reduced viscosity are measured as described in the description. a content of the acrylic acid ester-based rubbery polymer (A-a) is 10 to 40 wt%, with respect to 100 wt% of the methacrylic resin composition; a mean particle diameter d of the acrylic acid ester-based rubbery polymer (A-a) is 50 to 200 nm; a relationship between the mean particle diameter d (nm) of the acrylic acid ester-based rubbery polymer (A-a) and the cross-linking agent content w (wt%) in a monomer mixture used in the acrylic acid ester-based rubbery polymer (A-a) satisfies an inequation of 0.02d ≤ w ≤ 0.05d; a graft ratio of the acrylic graft copolymer is 60 to 105 %; and a reduced viscosity of components of the methacrylic resin composition, the components being soluble in methyl ethyl ketone, is 0.8 to 1.3 dl/g, wherein the graft ratio and the reduced viscosity are measured as described in the description.