[Problem to be Solved] Providing a seat pad that can provide good sitting comfortability with bonding between a ventilation member and an expanded resin foam included in the seat pad ensured. [Solution] A seat pad 10 including a ventilation member 20 having a function that lets air through to/from an outside, the seat pad 10 being formed by integral expansion molding of an expandable resin material M with the ventilation member 20 introduced therein, includes a covering member 30 that covers at least a part of the ventilation member 20 at an interface between the ventilation member 20 and the expandable resin material M, and the covering member 30 includes an impregnation inhibiting material having a function that inhibits infiltration of the expandable resin material M, the function being at least higher than that of the ventilation member 20.