PURPOSE: To easily automate all assembly processes and realize an assembly of required sealing performance by extending split faces of both housing portions transversely of an opening and through the axis of rotation of the pivot, and connecting a component with housing parts by material closing coupling.

CONSTITUTION: This cock valve includes a plastic housing 1 comprising a pair of housing parts 1a, 1b of the same constitution, and split faces 2 are extended transversely of an opening 3 and through the axis 4 of rotation of a ball plug 5. The ball plug 5 is provided with a pivot 6, the ball plug 5 and the pivot 6 are integrally formed and a seal ring 7 and a rubber ring 8 are disposed by one each between the housing parts 1a, 1b, and the seal ring 7 is energized toward the ball plug 5 under the action of pressing force by the rubber ring 8. A portion formed as a ring 9 having a trapezoidal section is arranged in an annular groove 10, and a seal surface of a seal element 12 provided on the pivot 6 is formed by the inner peripheral surface 11 of the ring 9 with a bearing seat of the pivot 6.