To provide a yarn accumulating device which can reduce the rise of traveling spun yarn from the flange part of a yarn accumulating roller.

The yarn accumulating device 24 includes a roller body 60 and a yarn hooking member 52. The roller body 60 is configured to be rotatingly driven and so that spun yarn is wound around the outer peripheral surface thereof. The yarn hooking member 52 is attached to the downstream side end of the roller body 60 in the yarn travelling direction, and assists the unwinding of the spun yarn Y by rotating relative to the roller body 60 while coming into contact with the spun yarn Y unwound from the roller body 60. A first flange part 64 increased in diameter toward the downstream side end in the yarn traveling direction is formed on the roller body 60. A straight line part 65L that is an arc having a smaller curvature than the arc of the contour 64L of the projection of the first flange part 64 viewed from the axial direction of the first flange part 64 is formed on at least a part of the contour 64L.