PURPOSE: To make a manufacturing work easy for joining existing urethane foam materials, and overlapping and jointing different types of materials as per specific request by integrally bonding and fixing a spring unit, a protective layer and a cushion layer using an adhesive.

CONSTITUTION: A spring unit 1 is constituted with many springs 11 and so forth laid in parallel, and the end ring portions 111a and 111b thereof are connected to each other with a helical wire 12 for forming the spring unit 1 into a flat shape. A protective layer 2 is added between the spring unit 1 and a cushion layer 3 for preventing the soft cushion layer 3 from being damaged due to the rigidity of the spring unit 1. In this example, a nonwoven cloth 21 is adopted as the protective layer 2. In addition, the springs 11 and the nonwoven cloth 21 are bonded and fixed to each other with an adhesive 41 at the spring end ring portions 111a and 111b connected with the helical wire 12. Furthermore, the cushion layer 3 comprises urethane foam 31 and nonwoven cloth 42 bonded to each other with an adhesive 42. According to the aforesaid construction, the bonding of different types of overlapped materials can easily be performed.