A design support system for circuit board includes: a noise source extracting unit for extracting a source of unwanted radiation noise which is generated from a circuit board mounted on an electronic equipment; a noise characteristics input unit for inputting noise characteristics of the unwanted radiation noise which is emitted by the extracted noise source; a noise attenuation ratio input unit for inputting an attenuation ratio of the unwanted radiation noise which is emitted by the noise source and propagated to a feed point of an antenna; a correlation value calculation unit for calculating a correlation value between the noise characteristics and the attenuation ratio of the unwanted radiation noise; and a comparator unit for comparing the calculated correlation value with a predetermined allowable value, whereby avoiding malfunction of an electronic equipment due to interference of unwanted radiation noises generated from the particular electronic equipment into the circuit board via the antenna.