Rubber-containing graft polymer, resin composition containing rubber-containing graft polymer, and shaped article thereof

A rubber-containing graft polymer having,

• a content of a methyl methacrylate-derived product of 43% or higher grafted to the rubber-containing graft polymer, and
• a content of an organic solvent soluble component with a styrene-equivalent molecular weight of 300,000 or more determined by integral molecular weight distribution of 10% or higher obtainable by freeze-grinding an organic solvent insoluble component of the rubber-containing graft polymer.

A rubber-containing graft polymer, which is obtainable by polymerizing, using a persulfate, a vinyl monomer for grafting containing 95% by mass or more of methyl methacrylate to rubber latex with a volume average particle size of 100 to 300 nm, which is obtainable by polymerizing, using a persulfate, 0.5 to 3.0 parts by mass of an aromatic vinyl monomer containing 100 parts by mass of acrylate (a1) and 0.1 to 0.7 parts by mass of allyl methacrylate (a2), or before polymerizing the vinyl monomer for grafting containing 95% by mass or more of the methyl methacrylate.