A methacrylic resin composition comprising 100 parts by mass of a methacrylic resin comprising 50 to 97% by mass of a methacrylic acid ester monomer unit, 3 to 30% by mass of a structural unit having a ring structure in the backbone, and 0 to 20% by mass of an additional vinyl monomer unit copolymerizable with a methacrylic acid ester monomer, and 0.001 to 0.2 parts by mass of a compound represented by the following general formula or, the methacrylic resin composition satisfying the following conditions and:: a weight-average molecular weight of the methacrylic resin composition as measured by gel permeation chromatography is 65,000 to 300,000, and: a mass ratio between the component and the structural unit having a ring structure in the backbone is 25 ≤ / ≤ 1000 wherein R represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an aromatic hydrocarbon group, wherein each carbon atom optionally has a sulfur atom, a nitrogen atom, an oxygen atom, or a phosphorus atom, and R' represents an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms, wherein each carbon atom optionally has a sulfur atom, a nitrogen atom, an oxygen atom, or a phosphorus atom, wherein R, R', and R" each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an aromatic hydrocarbon group, wherein each carbon atom optionally has a sulfur atom, a nitrogen atom, an oxygen atom, or a phosphorus atom, and R' and R" are optionally bonded to each other. 100 parts by mass of a methacrylic resin comprising 50 to 97% by mass of a methacrylic acid ester monomer unit, 3 to 30% by mass of a structural unit having a ring structure in the backbone, and 0 to 20% by mass of an additional vinyl monomer unit copolymerizable with a methacrylic acid ester monomer, and 0.001 to 0.2 parts by mass of a compound represented by the following general formula or, the methacrylic resin composition satisfying the following conditions and:: a weight-average molecular weight of the methacrylic resin composition as measured by gel permeation chromatography is 65,000 to 300,000, and: a mass ratio between the component and the structural unit having a ring structure in the backbone is 25 ≤ / ≤ 1000: a weight-average molecular weight of the methacrylic resin composition as measured by gel permeation chromatography is 65,000 to 300,000, and: a mass ratio between the component and the structural unit having a ring structure in the backbone is 25 ≤ / ≤ 1000 wherein R represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an aromatic hydrocarbon group, wherein each carbon atom optionally has a sulfur atom, a nitrogen atom, an oxygen atom, or a phosphorus atom, and R' represents an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms, wherein each carbon atom optionally has a sulfur atom, a nitrogen atom, an oxygen atom, or a phosphorus atom, wherein R, R', and R" each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an aromatic hydrocarbon group, wherein each carbon atom optionally has a sulfur atom, a nitrogen atom, an oxygen atom, or a phosphorus atom, and R' and R" are optionally bonded to each other.