PURPOSE: To enable holding of a constant quantity of outflow water for a long period by a method wherein a time delay device comprises an upper cylinder, a lower cylinder, a stroke regulating part, a piston member, and an orifice having a rodform member.

CONSTITUTION: When a control lever 14 is pressed downward, a contact plate 44 is pressed, a stroke regulating part 4 is lowered, and a piston member 5 is pressed downward. Water in a lower cylinder 32 is forced to flow through an orifice hole 61 in the direction of a coupling pipe 111, and a rodform member 62 of a stainless wire is moved until a lock part 64 is locked to the orifice hole 61. When the lever 14 is released from press, water flows in a cylinder 32 through the hole 61 simultaneously with restoration of a second spring 54. The member 62 is vertically moved within the hole 61 between lock parts 64 as upper and lower parts to perform cleaning of the hole 61. This constitution enables holding of a set constant quantity of outflow water for a long period.