A carrier, including: a main body, including a main rod and a connecting rod, the main rod having at least one supporting rod for supporting a bicycle at an end thereof, the connecting rod and the main rod being pivotally connected by a pivot axle, the connecting rod being adapted for connecting with a vehicle; a sliding groove, formed on one of the main rod and the connecting rod, the pivot axle being received in the sliding groove so that the main rod and the connecting rod are relatively slidable between a first position and a second position; a positioning assembly, including a positioning portion, a positioning element and an elastic element, the positioning portion being arranged on one of the main rod and the connecting rod, the positioning element being arranged on the other one of the main rod and the connecting rod, the elastic element being arranged between the main rod and the connecting rod so that the main rod and the connecting rod tend to retain at the first position; characterized in that the positioning portion includes an arch-shaped section and two recesses formed on the two opposite ends of the arch-shaped section, wherein, when the main rod and the connecting rod are at a first position, the positioning element is received in one of the recesses of the positioning portion and the main rod and the connecting rod are not pivotable with respect to each other due to an elastic force of the elastic element; wherein, when the main rod and the connecting rod are at a second position, the positioning element is not received in one of the recesses of the positioning portion and abuts against the arch-shaped section and the main rod and the connecting rod are pivotable with respect to each other. a main body, including a main rod and a connecting rod, the main rod having at least one supporting rod for supporting a bicycle at an end thereof, the connecting rod and the main rod being pivotally connected by a pivot axle, the connecting rod being adapted for connecting with a vehicle; a sliding groove, formed on one of the main rod and the connecting rod, the pivot axle being received in the sliding groove so that the main rod and the connecting rod are relatively slidable between a first position and a second position; a positioning assembly, including a positioning portion, a positioning element and an elastic element, the positioning portion being arranged on one of the main rod and the connecting rod, the positioning element being arranged on the other one of the main rod and the connecting rod, the elastic element being arranged between the main rod and the connecting rod so that the main rod and the connecting rod tend to retain at the first position; characterized in that the positioning portion includes an arch-shaped section and two recesses formed on the two opposite ends of the arch-shaped section, wherein, when the main rod and the connecting rod are at a first position, the positioning element is received in one of the recesses of the positioning portion and the main rod and the connecting rod are not pivotable with respect to each other due to an elastic force of the elastic element; wherein, when the main rod and the connecting rod are at a second position, the positioning element is not received in one of the recesses of the positioning portion and abuts against the arch-shaped section and the main rod and the connecting rod are pivotable with respect to each other.