A drilling tool comprising: a cutting insert, wherein the cutting insert has a cutting edge at a front end portion; a main body, wherein the main body is mounted with the cutting insert; a hollow discharge channel, wherein the hollow discharge channel is formed inside the main body, and the hollow discharge channel has a curved surface for guiding a chip in a direction towards a base end portion opposite to the front end portion, wherein the hollow discharge channel is formed between a rotation axis of the drilling tool and the outer circumferential surface, wherein the curved surface is an inclined surface configured to apply an urging force on the chip in a direction towards the base end portion during rotation of the drilling tool, wherein the drilling tool is provided with a plurality of cutting inserts, and a plurality of discharge channels being formed to extend from the front end portion to the base end portion, and the number of the discharge channels are same as the number of the cutting insert, wherein the plurality of discharge channels are axisymmetrical about the rotation axis of the drilling tool as a center, wherein the drilling tool further comprises a supporting member, the supporting member is mounted on the base end portion of the main body and supports the main body, and is provided with a hollow flow channel in communication with the discharge channel of the main body, wherein the drilling tool further comprises a cutting oil feed passage for feeding cutting oil; the drilling tool is characterised in that: the curved surface is formed with a helical shape around the rotation axis of the drilling tool, and in that the discharge channels are connecting with each other during extending. a cutting insert, wherein the cutting insert has a cutting edge at a front end portion; a main body, wherein the main body is mounted with the cutting insert; a hollow discharge channel, wherein the hollow discharge channel is formed inside the main body, and the hollow discharge channel has a curved surface for guiding a chip in a direction towards a base end portion opposite to the front end portion, the hollow discharge channel is formed inside the main body, and the hollow discharge channel has a curved surface for guiding a chip in a direction towards a base end portion opposite to the front end portion, wherein the hollow discharge channel is formed between a rotation axis of the drilling tool and the outer circumferential surface, wherein the curved surface is an inclined surface configured to apply an urging force on the chip in a direction towards the base end portion during rotation of the drilling tool, wherein the drilling tool is provided with a plurality of cutting inserts, and a plurality of discharge channels being formed to extend from the front end portion to the base end portion, and the number of the discharge channels are same as the number of the cutting insert, wherein the plurality of discharge channels are axisymmetrical about the rotation axis of the drilling tool as a center, wherein the drilling tool further comprises a supporting member, the supporting member is mounted on the base end portion of the main body and supports the main body, and is provided with a hollow flow channel in communication with the discharge channel of the main body, wherein the drilling tool further comprises a cutting oil feed passage for feeding cutting oil; the drilling tool is characterised in that: the curved surface is formed with a helical shape around the rotation axis of the drilling tool, and in that the discharge channels are connecting with each other during extending. the curved surface is formed with a helical shape around the rotation axis of the drilling tool, and in that the discharge channels are connecting with each other during extending.