The present invention relates to a heater block for a rapid thermal processing apparatus, and more particularly, to a heater block in which heating lamps are densely arranged in a tessellation. The tessellation has a structure such that the plurality of heating lamps are arranged at right angles to form a zigzag line, and the thus-formed zigzagged line is repeated such that the zigzagged line is combined with the adjacent zigzagged line. According to the present invention, a temperature gradient caused by a void between heating lamps is prevented, and heating lamps are densely arranged to increase heat density for a heat radiation area as opposed to conventional heater blocks, thus achieving improved heat treatment efficiency using less energy. In addition, fully uniform temperature control is enabled, in terms of sector allocated temperature control, even when the area to be independently controlled is enlarged as opposed to conventional heater blocks, thereby simplifying the configuration of a temperature control circuit.