A cutting edge adjustment device for a cutting tool for adjusting the position of a cutting edge of a cutting insert by causing movement of the cutting insert, the cutting edge adjustment device comprising: at least one rotary member for producing the movement; a cartridge with the cutting insert fixed thereto; and a tool body on which the cartridge is mounted, wherein the rotary member is formed into a shape comprising at least one substantially cylindrical portion (17, 18) having an outer peripheral surface whose radius is constant and at least one cam portion having a cam face whose radius is gradually increased in a manner corresponding to the amount of the movement, wherein the rotary member includes first and second substantially cylindrical portions (17, 18), each having a constant radius, the first substantially cylindrical portion, the cam portion, and the second substantially cylindrical portion being connected to each other in this order along the rotational center axis, wherein the rotary member is pressed against the cutting insert via the cartridge by the action of the cam face according to the rotation of the rotary member on the rotational center axis, so as to adjust the position of the cutting edge, wherein the cartridge has a portion adapted to abut against either one of the substantially cylindrical portion (17, 18) and the cam portion, characterised in that the tool body has a portion adapted to abut against the other one of the substantially cylindrical portion (17, 18) and the cam portion, wherein a position at which the cam face of the cam portion abuts against the portion adapted to abut against the cam is varied according to the rotation of the rotary member, so that the rotary member presses the cartridge so as to adjust the position of the cutting edge. at least one rotary member for producing the movement; a cartridge with the cutting insert fixed thereto; and a tool body on which the cartridge is mounted, wherein the rotary member is formed into a shape comprising at least one substantially cylindrical portion (17, 18) having an outer peripheral surface whose radius is constant and at least one cam portion having a cam face whose radius is gradually increased in a manner corresponding to the amount of the movement, wherein the rotary member includes first and second substantially cylindrical portions (17, 18), each having a constant radius, the first substantially cylindrical portion, the cam portion, and the second substantially cylindrical portion being connected to each other in this order along the rotational center axis, wherein the rotary member is pressed against the cutting insert via the cartridge by the action of the cam face according to the rotation of the rotary member on the rotational center axis, so as to adjust the position of the cutting edge, wherein the cartridge has a portion adapted to abut against either one of the substantially cylindrical portion (17, 18) and the cam portion, characterised in that the tool body has a portion adapted to abut against the other one of the substantially cylindrical portion (17, 18) and the cam portion, wherein a position at which the cam face of the cam portion abuts against the portion adapted to abut against the cam is varied according to the rotation of the rotary member, so that the rotary member presses the cartridge so as to adjust the position of the cutting edge.