A semiconductor package of superior high frequency characteristics enabling easy mounting of a large-sized capacitor and thereby enabling fluctuation of the power supply voltage to be suppressed and enabling a reduction of the inductance of the wiring portion connecting the capacitor and a connection terminal, that is, a semiconductor package mounting a capacitor for suppressing fluctuation of a power supply voltage, wherein the capacitor is comprised of, in an attachment hole passing through the board in the thickness direction, a conductor wire to be connected to a connection terminal of a semiconductor chip at one end, a high dielectric constant material covering the conductor wire at a predetermined thickness, and a conductor layer arranged between the outer circumference of the high dielectric constant material and the inner wall of the attachment hole, provided as a coaxial structure having the conductor wire at its center, and a method of production of the same.