To suppress wear and damage of a pipe line and to lengthen the life of the pipe line of the pipe by setting a center of gravity position of a blade to a position recovering a sliding edge part to a lower side of an inner wall of the pipe line.

Other edge parts 18 except a sliding edge part 17 are formed into a circular arc shape of a radius R2 shorter than the sliding edge part 17. The radius R2 is formed into a length in which space of a degree without hindering a degree of rotation freedom of a blade can be kept within a hollow part of a pipe line 10 of a pipe conveyor is formed. In the relation to the size of the blade, the edge part 18 is formed into a circular arc shape in which a radius R2 of a degree keeping space of substantial 20% to 30% of the hollow part of the pipe line 10 is set but the edge part 18 is allowable if the edge part 18 is in the range without hindering rotation. In this blade 7, the center of gravity position is set to a low position in which a sliding edge part 17 is recovered at an inner wall bottom part of the pipe line 10.