To obtain a methyl methacrylate resin composition having improved processability so that the surface properties of a formed article are excellent.

This methyl methacrylate resin composition is obtained by compounding a methyl methacrylate resin (A) with a polytetrafluoroethylene- containing mixed powder (B) consisting of polytetrafluoroethylene particles having particle diameters of 10 μm or less and an organic polymer in such a manner that the polytetrafluoroethylene component is 0.0001-20 pts.wt. based on 100 pts.wt. of the component (A).