A bicycle lock includes a first part and a second part located close to bicycle wheels by two bolts and two respective protection members are connected to the first part and the second part respectively. The protection members cover the heads of the bolts so that the unauthorized person cannot access the bolts to detach the bicycle lock from the bicycle. A lock rod is connected to the first part which is pivotable about the bolt corresponding thereto so as to be inserted into the second part to lock the wheel.
