This invention provides a fireproof separator board, which is made of a flame-retardant, high temperature resistant material and disposed within an insulating casing of an electrical device, for preventing the heat generated by the electrical components of the electrical device from being conducted to the insulating casing. This invention also provides a plug-based circuit interrupter that includes the fireproof separator board. The fireproof separator board and the plug-based circuit interrupter of this invention can effectively prevent high temperature and fire caused by the electrical components that could melt the casing.