To efficiently spray coolant without reducing tip support force at the flank side on the whole of the width part of a major cutting edge for cutting, regardless of a cutting blade shape and a width of cut, without causing complication of a shape of a coolant outlet provided in a holder, in a cutting tool for turning.

A restriction wall 31 with a restriction part 35 is set up and formed in the circumferential edge of a seat surface 2 of a holder 11, and a coolant outlet 55 is opened in the restriction wall 31. A board wall 41 for surrounding a supporting member 61 while holding a gap k is set up and formed in the circumferential edge of a seat surface 23. A cutting insert 71 is seated on the seat surface 23 through the supporting member 61, and a flank 75 is restricted and fixed by the restriction part 35. The gap k is held between a flank 65 of the supporting member 61 and the restriction wall 31 and the board wall 41. A coolant is ejected from the outlet 55 to the gap k, and can be spouted as a thin film flow toward a major cutting edge 72 from the side of the seat surface 23 along the flank 65, and thereby the coolant can be sprayed efficiently.