METHOD OF PRODUCING (METH) ACRYLIC RESIN COMPOSITION

A method of producing a (meth) acrylic resin composition. The method comprises a step of continuously feeding a reaction raw material including a chain transfer agent, a radical polymerization initiator and a monomer mixture comprising 80 to 100 % by mass of methyl methacrylate and 20 to 0 % by mass of an alkyl acrylate to a tank reactor through two or more feeding ports; a step of bulk polymerizing the monomer mixture in the tank reactor until a polymerization conversion of 40 to 70 % by mass to prepare a reaction product; and a step of removing the monomer mixture from the reaction product. The perfect mixing time (?M [hr]) of the tank reactor, the half-life (?1 / 2 [hr]) of the radical polymerization initiator at the temperature in the tank reactor, the stirring power (PV [kW/m3 ]) of the tank reactor, the mean residence time (? [hr]) of the reaction raw material in the tank reactor, and the concentration (I [ppm]) of the radical polymerization initiator in the reaction raw material satisfy the following relationships: ?M > ?1 / 2 , and PV ???I??1 / 2 < 4.