An electroconductive plate is prepared by molding an electroconductive resin composition comprising an electroconductive agent and a radical-polymerizable thermosetting resin system having an acid value in a specific range by a resin molding method. The electroconductive agent may be a carbon powder. The radical-polymerizable thermosetting resin system may comprise a radical-polymerizable resin and a radical-polymerizable diluent. The double bond equivalent of the radical-polymerizable resin is preferably about 200 to 1000. The glass transition temperature of the hardened product is preferably not lower than 120.degree. C. The proportion (weight ratio) of the electroconductive agent relative to the radical-polymerizable thermosetting resin system [the former/the latter] is about 55/45 to 95/5.