To provide a vacuum type draining system easy to construct without installing electric equipment for each water collecting recessed part only if installing electric equipment for a negative pressure source, or gradient management of a drain pipe (conduit).

A drain pipe 18 is disposed within a space 10d of an underground structure (common channel 10), so that water in the drain pipe 18 is collected by a pressure difference between atmospheric pressure and negative pressure. A water collecting recessed part 17 is formed in a bottom part 10e of the space 10d, and the drain pipe 18 is disposed along the bottom part 10e. The drain pipe 18 includes fluid retaining parts 19 provided at predetermined intervals, each fluid retaining part 19 being formed by successively connecting a horizontal part 19a, an upward inclination part 19b, a horizontal part 19c, a downward inclination part 19c and a horizontal part 19d, and a water absorption pipe 33 with the lower end being disposed within the water collecting recessed part 17 is connected to the drain pipe 18 through a vacuum valve unit 32.