<p>An end mill enabling the suppression of vibration in cutting and the improvement of chip discharging property to provide both high cutting efficiency and long tool life. The first clearance angle (a<SUB>1</SUB>) of the outer peripheral edges (4a to 4d) of the end mill (1) is set to a range of more than 0° to approximately 3°, the first clearance width (t<SUB>1</SUB>) of the outer peripheral edges (4a to 4d) is set to a range of approximately 0.005D or more to approximately 0.03D where the outside diameter is (D), and a helix angle (?) is set to an equal value for all the outer peripheral edges (4a to 4d) in a range of approximately 35° or more to approximately 40°. As a result, the vibration in cutting can be suppressed, and the chip discharging property can be improved.</p>
