For enabling accurate and efficient cutting work on a narrow area, in a hydraulic chuck configured such that a pressurization fluid pressurized by a push member (8b) is fed through a pressurization passage (8) to a pressurization chamber (6) to reduce a diameter of an elastic deformable part (2b), the hydraulic chuck includes a body (1) having a flange accommodating part (5a) opening at a small-diameter portion at a tip end of the body and a sleeve accommodating part (5b) opening in a bottom face of the flange accommodating part (5a), and a sleeve (2) having a hole (2a) in which a gripped object is inserted, the sleeve being engageable and insertable with/to the sleeve accommodating part (5b) from a leading end side of the flange accommodating part (5a), the sleeve (2) forming the pressurization chamber (6) reserving therein an amount of the pressurization fluid between this sleeve (2) and the sleeve accommodating part (5b), the sleeve (2) having a flange (7) engageable with the flange accommodating part (5a).