The invention relates to the field of bike locks, and aims at providing a public bike lock. The public bike lock comprises a shell, a driving device, a first lock tongue and a second lock tongue. A straight-line-shaped sliding channel which is cut through frontward to backward is arranged inside the shell. The two ends of the sliding channel are formed into a first outlet and a second outlet. The first lock tongue and the second lock tongue are symmetrically and slidably arranged in the sliding channel. The driving device drives the first lock tongue and the second lock tongue to move in the sliding channel in the same or opposite direction. The public bike lock has the advantages that due to the fact that the two lock tongues are arranged in the same shell, the integration of the public bike lock is achieved, producing and assembling are convenient, the production efficiency is improved, the driving device is adopted to drive the first lock tongue and the second lock tongue at the same time, the structure is simple, and the cost is lowered.