Drain pipe assembly for installation of washstand

A drain pipe assembly for installation of a basin, comprising:

• a drain pipe (111) which is inserted in a drain port formed in a base of basin (1) and has a flange (113) whose upper end is caught by the drain port;
• and
• a fastening member which fixes the basin (1) against the flange (113),
• wherein the fastening member is formed to downwardly pull the drain pipe (111) which is exposed below the basin (1) to upwardly press the basin (1), thereby fastening the basin (1) and the drain pipe (111), and
• wherein the fastening member includes:
• a sliding member (121) which is formed in such a manner that the drain pipe (111) exposed below the basin (1) is slidably inserted,
• a clamp member (141) which is positioned between the sliding member (121) and the drain pipe (111) and clamps the drain pipe (111) to be held in the sliding member (121), and
• a first spring member (125) which receives the drain pipe (111) in a vertical direction and is provided between the basin (1) and the sliding member (121) to downwardly press the sliding member (121).