PURPOSE: To dispense with pipe connection in a unit in an installation site.

CONSTITUTION: The whole set of a sink (a), a water supply pipe 1 and a drain pipe 2 around the sink, an electric water storage type heater (b), etc., is assembled as a unit in a cabinet B at the front face of a rear face board. A water supply rising pipe 10 and a rising drain pipe 20 are provided vertically and parallelly with a partition 40 between them at the side of cabinet B to form a kitchen unit A. The water supply pipe 1 and the drain pipe 2 are connected to the water supply rising pipe 10 and the rising drain pipe 20 respectively. The water supply rising pipe 10 and the rising drain pipe 20 can be connected to the water supply rising pipe 10 and the rising drain pipe 20 of the kitchen unit A on a different floor or a water supply pipe 100 and a drain pipe 200 laid separately in the building, through an attachment 30 for connection of pipes.