The interposer includes a glass substrate 46 with first through-electrodes 47 buried in; a plurality of resin layers 68, 20, 32 supported by the glass substrate; thin film capacitors 18a, 18b buried between a first resin layer 68 of the plural resin layers and a second resin layer 20 of the plural resin layers and including the first capacitor electrodes 12a, 12b, the second capacitor electrodes 16 opposed to the first capacitor electrodes 12a, 12b, and a dielectric thin film 14 of a relative dielectric constant of 200 or above formed between the first capacitor electrode 12a, 12b and the second capacitor electrode 16, and the second through-electrodes 77a, 77b penetrating the plural resin layers 68, 20, 32, electrically connected to the first through-electrode 47 and electrically connected to the first capacitor electrode 12a, 12b or the second capacitor electrode 16.