In a high-frequency module, intermediate ground electrodes are provided between a common ground electrode and upper-surface ground electrodes for mounting high-frequency components on an upper surface of a multilayer substrate. With regard to the number of via-hole conductors interconnecting ground electrodes, the number of via-hole conductors between the intermediate ground electrodes and the common ground electrode is larger than the number of via-hole conductors between the upper-surface ground electrodes and the intermediate ground electrodes.