The invention provides a seat cushion which can reduce working time for machining a linear member and furthermore can realize high comfort in sitting. One part of skin material (4) is drawn into the groove part (longitudinal groove (12)) formed on the surface (16) of a cushion body (11). The skin material (4) is mounted on the embedded linear member (20) which is made of synthetic resin. Because the cushion body (11) is provided with through holes (15) which penetrate through the groove part (longitudinal groove (12)) and the back surface (17) of the cushion body (11), compared with a condition without the through hole (15), a spring feeling can be reduced, thereby realizing high comfort in sitting. Because one part of the linear member (20) is exposed from the through holes (15), bending of the linear member (20) for dodging the through holes (15) is not required. Therefore working time for machining the linear member (20) can be reduced.