A wiring board comprising: a core board including a core body and a ceramic sub-core which is accommodated in a sub-core accommodation space that is a through-hole that communicates with major surfaces of the core body or a recess having an opening in a first major surface of the core body; and wiring laminates each formed by resin insulating layers and conductor layers laminated on each of major surfaces of the core board, wherein: a groove-filling portion which fills a gap between the core body and the ceramic sub-core is integral with a lowest resin insulating layer of the first-major-surface-side wiring laminate; and via conductors that are connected to respective conductor patterns formed on a first major surface of the ceramic sub-core penetrate through the lowest resin insulating layer.