PROBLEM TO BE SOLVED: To provide a polystyrene-based composite resin particle and method for producing the same capable of providing an expansion molded article excellent in compressive strength and capable of shortening the molding cycle, and to provide an expandable particle, an expanded particle and an expansion molded body.SOLUTION: The problem is solved by a polystyrene-based composite resin particle characterized in that: it is a polystyrene-based composite resin particle containing an ethylene-vinyl acetate copolymer resin and a polystyrene-based resin in a mass ratio of 50:50 to 15:85; the polystyrene-based composite resin particle comprises, in a TEM pictorial image obtained from an arbitrary observation point in the particle surface layer, polystyrene-based resin particulates having particle diameter of 0.25 to 0.80 μm within an area of a depth from a particle surface of 0.5 μm and a length of 5 μm; and the area ratio of the polystyrene-based resin particulate occupying the area is 5 to 30%
