The RF device of the present invention includes: a semiconductor substrate; and first and second semiconductor components provided on the substrate. Each of the components includes source electrodes, a gate electrode and a drain electrode. And multiple through holes, which pass through the substrate in the thickness direction, are opened in a region of the substrate between the two components. To enhance the effect of suppressing electrical interference between the components, a gap between two adjacent ones of the through holes is preferably smaller than the thickness of the substrate.