An adjustable hanging device includes a longitudinal body and an adjustable socket member. The longitudinal body has a hanging portion, a mounting portion extending downwardly from the hanging portion, and a guiding hole extending in the hanging portion along a transverse direction of the longitudinal body. The guiding hole has two transversely opposite stop ends. The adjustable socket member is formed with a hanging hole, and is slidable in the guiding hole along the transverse direction between the transversely opposite stop ends so as to adjust position of the hanging hole relative to the center of gravity of the total mass of the adjustable hanging device and at least one object mounted on the adjustable hanging device.