Disclosed are resin particles having excellent thermal decomposability and suitable hardness. The resin particles are cross-linked methacrylate resin particles obtained by polymerizing monofunctional methacrylate and polyfunctional methacrylate, wherein the blending amount of the monofunctional methacrylate is 60% by mass to 95% by mass and the blending amount of the polyfunctional methacrylate is 5% by mass to 40% by mass with respect to the total amount of methacrylate compound, being a raw material for the polymerization reaction; the number of carbon atoms in the ester substituent of the monofunctional methacrylate is 3 or less; and 5% mass reduction temperature of the cross-linked methacrylate resin particles as measured by thermogravimetric differential thermal analysis is 180° C. or more and 240° C. or less.