PURPOSE:To improve the bend rigidity and shear rigidity of rubber bellows and increase service life by laminating a reinforcement layer in the middle or inner side of two layers of reinforcement cords near the contacting parts of the rubber bellows contacting tightening rings at both ends. CONSTITUTION:A reinforcement layer 10 is laminated in the middle of two layers of reinforcement cords 7 or on the inner side of the reinforcement cords 7 near contacting parts of a rubber bellows 1 contacting tightening rings 4 at both ends. As a result, the bend rigidity and shear rigidity of the rubber bellows 1 near the contacting parts with the tightening rings 4 which have conventionally been most likely to be deformed and abraded are extremely increased. Deformation of a pneumatic spring is received by the part indicated by X before which a reinforcement layer 10 ends, and deformation quantity around the contacting parts near the part of X is reduced to half compared to conventional devices. Generation of cracks or abrasion at these parts can thus be held to the minimum, thereby the life of the rubber bellows 1 can be prolonged.