A high-frequency module is constituted by mounting a surface-acoustic-wave device on an insulating substrate constituting a surface-acoustic-wave-device mount substrate in which insulating substrate a plurality of insulating layers are laminated. A ring-shaped ground electrode of the insulating substrate is electrically connected to a predetermined conductor pattern formed on a back surface of the insulating substrate through a plurality of via-conductors including a via-conductor directly connected to the electrode. Among the plurality of via-conductors, via-conductors other than the via-conductor directly connected to the ring-shaped ground electrode are disposed outside a ring-shaped electrode region, as seen in plan view, where the ring-shaped ground electrode is formed.