An adjustable apparatus for adjusting the positions of a display is provided. The display includes a base, a supporting arm and a display unit. Two ends of the supporting arm are pivotably connected to the base and the unit. The adjustable apparatus at least comprises a leading rod disposed within the base and an operation block mounted on the leading rod. One end of the leading rod is connected to the supporting arm. There are an outer thread formed on the surface of the leading rod and an inner thread correspondingly formed within the operation block. When the operation block is operated, the inner thread of the operation block is engaged with the outer thread of the leading rod, and the leading rod can be moved forwards or backwards so as to drive the supporting arm to rotate and adjust the positions of the display unit.