To provide a vinyl chloride pipe line constituting member, which has good flexibility and impact resistance, is joined by adhesive, has good execution performance and is made of vinyl chloride resin composition and has good earthquake resistance.

In a vinyl chloride pipe line constituting member prepared by forming a vinyl chloride composition containing 100 pts.wt. of a vinyl chloride resin and 10 to 30 pts.wt. of plasticizer, a bending elastic modulus is set in the range of 5000 to 20000 kgf/cm2, and a balance stress reducing rate represented by an expression is set in the range of 40 to 100%. But a measuring temperature is 23°C initial stress is 1/2 of breaking stress (allowance ±5%), and balance stress is stress after 24 hours.