Insert

[Task] To provide an insert which is attached to a tool body of a hole machining tool, which can enhance movement balance and rigidity of the tool body by reducing portions cut out from the tool body, and which can simply adjust the position of the insert with high precision. [Means for Resolution] In an insert 50 attached to a hole machining tool having an attachment seat 31 and a pressing member 40 for pressing the insert 50 to adjust the position of a peripheral cutting edge in a diameter direction, the insert has a panel shape, one surface of the insert in the thickness direction becomes a seating surface 51, the other surface in the thickness direction becomes a peripheral flank surface 52, the surface facing the rear side in a tool rotation direction becomes a pressed surface 61 in a state that the insert is attached to the attachment seat 31, the side surface facing the front side in the tool rotation direction becomes an inclined surface 54, and a peripheral cutting edge is formed at a ridge portion on the outside of the inclined surface 54 in the diameter direction.