A yarn end untwisting pipe comprising a hollow pipe main body that extends in an axial direction (D1), the pipe main body including a first end in the axial direction (D1), and a second end that is provided on an opposite side of the first end , the first end and the second end are open ends, the pipe main body including an injection hole formed through a peripheral wall thereof, a first opening part , which is an inlet of the injection hole , is formed on an outer surface of the peripheral wall , and a second opening part , which is an outlet of the injection hole , is formed on an inner surface of the peripheral wall , at least a part of the second opening part is positioned closer to the second end than the first opening part , and each of the first opening part and the second opening part is an elongated hole that extends in a width direction (D3) that is orthogonal to the axial direction (D1), when viewed from a center line (L2) direction of the injection hole , characterized in that when viewed from the center line (L2) direction of the injection hole , the first opening part includes a first edge portion that extends in the width direction (D3); and a second edge portion that extends in the width direction (D3) and is parallel to the first edge portion , and is positioned closer to the first end than the first edge portion , and a maximum clearance (W3) of the first opening part in the width direction (D3) is larger than a clearance (W1) between the first edge portion and the second edge portion . the pipe main body including a first end in the axial direction (D1), and a second end that is provided on an opposite side of the first end , the first end and the second end are open ends, the pipe main body including an injection hole formed through a peripheral wall thereof, a first opening part , which is an inlet of the injection hole , is formed on an outer surface of the peripheral wall , and a second opening part , which is an outlet of the injection hole , is formed on an inner surface of the peripheral wall , at least a part of the second opening part is positioned closer to the second end than the first opening part , and each of the first opening part and the second opening part is an elongated hole that extends in a width direction (D3) that is orthogonal to the axial direction (D1), when viewed from a center line (L2) direction of the injection hole , characterized in that when viewed from the center line (L2) direction of the injection hole , the first opening part includes a first edge portion that extends in the width direction (D3); and a second edge portion that extends in the width direction (D3) and is parallel to the first edge portion , and is positioned closer to the first end than the first edge portion , and a first edge portion that extends in the width direction (D3); and a second edge portion that extends in the width direction (D3) and is parallel to the first edge portion , and is positioned closer to the first end than the first edge portion , and a maximum clearance (W3) of the first opening part in the width direction (D3) is larger than a clearance (W1) between the first edge portion and the second edge portion . <EOS>