Abstract: A tool holder holding in a fluid supply hole 3d having an inner diameter a tool 1 having the diameter of identical with or smaller than said inner diameter through a collet 2, wherein a fluid can be supplied from the fluid supply hole 3d to a fluid channel 1c of the tool 1, in the fluid supply hole 3d, a seal block 11 as a regulating means which regulates a flowing amount of the fluid to the fluid channel 1c of the tool 1 and the flowing amount of the fluid to the gap between the fluid supply hole and the tool 1 is provided slidably in the longitudinal direction of the fluid supply hole. The seal block 11 adheres close to the end of the tool 1 due to the fluid pressure in the fluid supply hole 3d and the fluid is supplied to the close adhesion portion, thereby the fluid flowing amount to the channel 1c of the tool 1 can be regulated.