A fast electric boiler functioning as an electric hot water-mat and a briquette boiler is provided to minimize the volume and the weight by forming a horizontal steam pipe instead of a vertical steam pipe. A fast electric boiler functioning as an electric hot water-mat and a briquette boiler comprises a boiler lid(10-3), a height adjusting screw supporting rod(11), a horizontal heating element(13), a horizontal steam pipe(16), a temperature controller(23), a water supplementing container(29), and an electric hot water-mat. The boiler lid has a rim surface(10-1), a pipe insertion hole(A,B), a radiator disk cover(14), and a switching unit. The water supplementing container supplements water by circulating hot water heated with the horizontal steam pipe through a heating pipe.