A seat core material of the present invention is a seat core material for vehicle including a thermoplastic resin expanded bead article and a frame member embedded in a peripheral edge portion of the expanded bead article. The frame member includes a front frame part, a rear frame part, and two side frame parts interconnecting the front frame part and the rear frame part. Slits crossing the two side frame parts are formed along a longitudinal direction with continuous parts left intact outside the side frame parts on both ends of the expanded bead article. The slit penetrates or does not penetrate the expanded bead article in a thickness direction. The continuous parts are formed in a curved shape or a bent shape.