PROBLEM TO BE SOLVED: To construct a fish-pass channel along which various fishes, etc., can go upstream even on condition of a steep slope, a small width or great fluctuations in water level on upstream and downstream sides, and which can suppress inflow of foreign matter.
SOLUTION: This fish-pass channel 2, which connects an upstream-side water area 3 with a downstream-side water area 4, is defined by a bottom part 5 and side walls 6a and 6b. In the channel 2, a plurality of partition walls 1 for separating the upstream and downstream sides are provided between the side walls 6a and 6b at each interval D1. An orifice 10 is formed in the partition wall 1, and opening surfaces of the adjacent orifices 10 are arranged in a state of being displaced in such a manner as be staggered on right and left sides, so as not to be completely superposed together in a flow direction. Consequently, even if the interval D1 is made shorter, it is made hard to bring about a state in which a flow runs down straightly between the adjacent orifices 10, the flow rate and flow velocity of the orifice 10 can be kept at/below a fixed level, and the flow velocity of the opening surface of the orifice 10 can be varied.