[Objective] To provide a multilayer wiring substrate in which, even when a core substrate is thinned, the core substrate can reliably accommodate a
capacitor.[Means for Solution] A multilayer wiring substrate 10 includes a sheetlike
capacitor element 101, a resin filler 92, and via conductors 43 and 47. A sheetlike
capacitor element 101 has an element main-surface 102 and an element back-surface 103, is configured such that a
dielectric layer 107 is sandwiched directly between a main-surface-side
electrode layer 105 exposed at the element main-surface 102 side and a back-surface-side
electrode layer 106 exposed at the element back-surface 103 side, and is accommodated at least partially in an
accommodation hole 90 such that a core main-surface 12 and the element main-surface 102 face the same direction. A resin filler 92 is charged into a gap between the sheetlike capacitor element 101 and an inner wall surface 91 of the
accommodation hole 90. The via conductors 43 and 47 are provided in at least interlayer insulating
layers 33 to 38 formed on the core main-surface 12 side, and are connected to at least the main-surface-side
electrode layer 105.