Cutting Tool with a Replaceable Blade Edge

A tip-replaceable cutting tool comprising:

• an insert attachment seat for removably attaching a cutting insert;
• and
• a substantially plate-shaped cutting insert installed in the insert attachment seat, wherein
• said insert attachment seat has a substantially flat bottom face, and first and second restraint wall faces which rise upward from said bottom face and are not in parallel with each other,
• an angle between the first and second restraint wall faces is smaller than an angle between two peripheral faces of the cutting insert respectively opposing the first and second restraint wall faces, as viewed from a side opposing the bottom face,
• a lower face of said cutting insert contacts said bottom face and said two peripheral faces contact said first and second restraint wall faces respectively opposing the peripheral faces,
• a first of said two peripheral faces of the cutting insert contacts said first restraint wall face in a substantially parallel posture with an extending direction of said first restraint wall face, and
• a second of said two peripheral faces is inclined relative to an extending direction of said second restraint wall face, and contacts said second restraint wall face at an end portion of said second restraint wall face.