To provide an inflow part structure of a longitudinal pipe with a spiral guide passage, smoothly guiding a fluid flowing into the longitudinal pipe to the spiral guide passage even when a plurality of inflow pipes are connected to a manhole.

The plurality of inflow pipes 11, 12 are connected to the upper pipe wall of the manhole 1 to have a difference in level, and inflow ports 22, 23 corresponding to the respective inflow pipes 11, 12 are provided on the upside of the longitudinal pipe body 21. A guide wall 32 connecting the inner surface of the manhole 1 and the outer surface of the longitudinal pipe body 21 to guide a fluid so that the fluid flowing down from the ends of the respective inflow pipes 11, 12 smoothly flows into the longitudinal pipe body 21 is erected on an upper slab 13 to form an inflow part 3.