A tool chucking apparatus includes a fastening member, a collet, a holding member and an extension member. The fastening member has a first housing space to hold the collet. The collet has pawl structures spaced in an annular manner and formed in a conical structure. The conical structure has a top end directing towards the fastening member. The extension member includes a support portion and an anchor portion coupled together. The support portion has another end tightly coupled with the collet and the fastening member. The anchor portion has another end tightly coupled with the holding member. The support portion is selectable at a desired length specification according to the cutter or tool. The fastening member, collet, holding member and extension member are hollow in the center thereof to form an installation passage after assembly to hold the cutter or tool.