The purpose of the invention is to provide a methacrylic resin composition which has excellent continuous productivity and less content of foreign matters and can prepare a moulded body with excellentphysical property and appearance and also provide a preparation method of the methacrylic resin composition, particles and the moulded body. According to the invention, the composition contains methacrylic resin which contains more than 50 mass percent of a methacrylate monomer unit (A) and has ring structure, a glass-transition temperature is 110 DEG C to 160 DEG C, a particle counter is used for measuring, and each 1g contains less than 100 of foreign matters with partical sizes of more than 10[mu]m and less than 20[mu]m; the prepare method comprises: when an extruder runs, delivery volumes(delivery volumes/number of holes) of the methacrylic resin composition from holes of each die is more than 5kg/(hr*number) and less than 30 kg/(hr*number).