A foldable lock includes a first body, a second body, and a rod set including a plurality of pivotally connected locking rods. The first body and the second body are separately pin-connected to a locking rod. The first body, the second body, and the plurality of the locking rods can have rotational movement in two-dimensional space with the pin joint as a rotation axis, which affects relative position of the first body and the second body. The first body has a first mating face, and the second body has a second mating face. The mating faces can separate from or mate with each other. The bodies and the rod set constitutes a closed ring by means of matching of the mating faces; at this time, a locking operation will let the mating faces be unable to separate from each other, namely the bodies will not move relatively. At the same time, if the closed ring does not circle any object, the rod set can further be rotated to a stacking state for storage.