Rotary tool and method for manufacturing machined product

A rotary tool, having a columnar shape extending along a rotation axis from a first end toward a second end and comprising:

• an outer peripheral surface;
• a first flute extending spirally around the rotation axis from the first end toward the second end and having a first helix angle;
• a second flute extending spirally around the rotation axis from the first end toward the second end and having a second helix angle;
• a first cutting edge located at an intersection of the outer peripheral surface and the first flute;
• and
• a second cutting edge located at an intersection of the outer peripheral surface and the second flute, wherein
• the first helix angle is a positive value, and the second helix angle is a negative value,
• the first flute intersects with the second flute, and the first cutting edge connects to the second cutting edge,
• the outer peripheral surface comprises
• a first outer peripheral surface extending along the first cutting edge and the second cutting edge, and
• a second outer peripheral surface located on a rear side in a rotation direction of the rotation axis with respect to the first outer peripheral surface,
• the first outer peripheral surface comprises
• a first flank surface extending along the first cutting edge, and
• a second flank surface extending along the second cutting edge, and
• the first flank surface comprises a first enlarged part whose width in a direction orthogonal to the first cutting edge increases as coming closer to the second flank surface.