Cutting insert and method for manufacturing cutting insert

A cutting insert comprising:

• a rake face;
• a flank face continuous to the rake face;
• and a cutting edge constituted of a ridgeline between the rake face and the flank face, wherein
• a coolant flow path is provided inside the cutting insert,
• one end portion of the coolant flow path opens in the flank face to form a coolant ejection hole,
• the flank face is provided with a coolant guide groove extending from the coolant ejection hole toward the cutting edge with a base end portion of the coolant guide groove being connected to the coolant ejection hole and with a front end portion of the coolant guide groove being disposed at a position close to the cutting edge relative to the base end portion,
• the coolant flow path is inclined such that a distance between the coolant flow path and the cutting edge becomes smaller as the coolant flow path is closer to the flank face,
• the cutting insert is constituted of a cutting edge tip composed of cubic boron nitride and a substrate composed of cemented carbide,
• the cutting edge tip is attached to the substrate,
• the coolant ejection hole is at the flank face which is located at the substrate, and
• the coolant guide groove extends into the flank face of the cutting edge tip.