Locating/controlling structure for telescopic tube

A locating/controlling structure for telescopic tube comprising an outer tube and an inner tube telescopically nested in the outer tube, the outer tube having an elliptic cross-section, a handle being fitted on one end of the outer tube, the handle having a close end having an inner face and an outer face, the inner face being formed with an annular groove in which one end of the outer tube is inlaid, the close end being formed with a through hole in which a rotary button is rotatably disposed, the rotary button being formed with a projecting post in cooperation with the through hole, one end of the projecting post distal from the rotary button having an annular engaging hook, whereby the projecting post can be passed through the through hole to engage the engaging hook with the inner face of the close end of the handle, the rotary button being connected with an elliptic rod passing through the outer tube and extending in axial direction of the outer tube, the inner tube having an elliptic cross-section and being fitted in the other end of the outer tube, one end of the inner tube fitted in the outer tube being provided with a cock body formed with a central circular hole through which the elliptic rod is passed, the cock body having a stop section protruding from the inner tube, the stop section having a cross-section with a shape corresponding to inner circumference of the outer tube, the stop section being formed with two radially opposite receptacles respectively radially outward passing through the stop section from the circular hole, a movable block being disposed in each of the receptacles, each movable block having a contacting face complementary to the inner circumference of the outer tube, when the rotary button is turned to drive the elliptic rod to rotate about the axis thereof, the elliptic rod pushing the two movable blocks to radially outward move, whereby the contacting faces of the movable blocks press and abut against the inner circumference of the outer tube.