Rotary tool and method for manufacturing machined product

A rotary tool comprising:

• a body having a rod-like shape and extending along a rotation axis from a first end toward a second end,
• wherein
• the body comprises:
• a cutting edge located at the first end;
• and
• a first groove extending in a spiral manner from the cutting edge toward the second end,
• the first groove comprises:
• a first region having a first helix angle;
• a second region located closer to the second end than the first region and having a second helix angle;
• a third region located closer to the second end than the second region and having a third helix angle;
• a fourth region located between the first region and the second region and having a fourth helix angle;
• and
• a fifth region located between the second region and the third region and having a fifth helix angle,
• the second helix angle is less than the first helix angle and greater than the third helix angle,
• the fourth helix angle and the fifth helix angle each decrease from a side of the first end toward the second end,
• a decreasing range of a value of the fourth helix angle is less than a decreasing range of a value of the fifth helix angle, and
• a length of the fourth region in a first direction along the rotation axis is greater than a length of the fifth region in the first direction.