A folding box (100), comprising: a bottom plate (1), and a pair of first side plates (2) and a pair of a second side plates (3) capable of being folded with respect to the bottom plate (1). The first side plates (2) and the second side plates (3) are releasably interlocked via a locking mechanism (4). The locking mechanism (4) comprises a handle (41), a locking member (42), and a guidance feature (31). When the first side plates (2) and the second side plates (3) are in a locked state, the handle (41) restricts the position of the locking member (42), thus limiting the movement of the locking member (42), when the handle (41) restricts the position of the locking member (42), thus limiting the movement of the locking member (42), when the handle (41) moves and provides the locking member (42) space required for movement of the locking member (42), the locking member (42) cooperates with the guidance feature (31) to drive the locking member (42) to move so as to unlock the same. When the folding box is empty and recycled, the side plates are easy and convenient to unlock, and are difficult to be unlocked by an accidental triggering when using.