Abstract: Flexible expansion joints utilized for coupling conduit pipes or pipelines for conveyance, supply, service and drainage of service water, sewage, industrial water, etc. are provided, which comprise a tubular flexible body portion and two side joint portions. The tubular flexible body portion comprises bias cord reinforcement layer(s) provided circumferentially at a "cord angle" of 10.degree. to 45.degree.. Alternatively, it may further comprise circumferential cord reinforcement layer(s) circumferentially provided at a "cord angle" of 0.degree. to 25.degree. inside the bias cord reinforcement, and a plurality of coaxial rigid rings. The flexible expansion joints have good pliability, flexibility, vibration absorbing property, internal and external pressure resistance, durability, anti-deformation property and the like.