A tool holder , comprising a body that has a body inner peripheral surface and a body outer peripheral surface, the body having a shank part on a rear end side and a tool gripping part on a front end side, wherein the body has a first elastic part between the shank part and the tool gripping part , the first elastic part has a plurality of first voids (232a, 232b, 232c, 232d, 232e, 235a 235b, 235c, 235d, 235e) extending along a circumferential direction and a plurality of second voids extending along an axial direction, the first and second voids extending between the body inner peripheral surface and the body outer peripheral surface, and is configured to be elastically deformable along the axial direction and the circumferential direction, a first void of the plurality of first voids extends along the circumferential direction so as to at least partially overlap with at least one of the other first voids of the plurality of first voids in the circumferential direction, and a second void of the plurality of second voids extends along the axial direction so as to at least partially overlap with at least one of the other second voids of the plurality of second voids in the axial direction, wherein the plurality of first voids and the plurality of second voids are grouped into first void groups including first voids and second voids and second void groups including first voids and second voids , first voids and second voids included in each of the first void groups are continuous to each other and first voids and second voids included in each of the second void groups are continuous to each other, the first void groups and the second void groups are alternately arranged along the circumferential direction such that a first void group and a second void group which are adjacent to each other in the circumferential direction partially overlap with each other in the circumferential direction and the axial direction. the body has a first elastic part between the shank part and the tool gripping part , the first elastic part has a plurality of first voids (232a, 232b, 232c, 232d, 232e, 235a 235b, 235c, 235d, 235e) extending along a circumferential direction and a plurality of second voids extending along an axial direction, the first and second voids extending between the body inner peripheral surface and the body outer peripheral surface, and is configured to be elastically deformable along the axial direction and the circumferential direction, a first void of the plurality of first voids extends along the circumferential direction so as to at least partially overlap with at least one of the other first voids of the plurality of first voids in the circumferential direction, and a second void of the plurality of second voids extends along the axial direction so as to at least partially overlap with at least one of the other second voids of the plurality of second voids in the axial direction, wherein the plurality of first voids and the plurality of second voids are grouped into first void groups including first voids and second voids and second void groups including first voids and second voids , first voids and second voids included in each of the first void groups are continuous to each other and first voids and second voids included in each of the second void groups are continuous to each other, the first void groups and the second void groups are alternately arranged along the circumferential direction such that a first void group and a second void group which are adjacent to each other in the circumferential direction partially overlap with each other in the circumferential direction and the axial direction. <EOS>