A bicycle rack includes two rods with two plates pivotably connected therebetween and a secure device is connects the two plates. The secure device includes a locking member with a latch which extends through the body of the secure device and is engaged with two aligned apertures respectively defined through the two plates. The locking member is controlled by a lock device so that the latch is not disengaged form the apertures of the plates unintentionally. An operation member is connected to one of the two rods and a locking ring is connected to the other rod so as to be hooked on the operation member to clamp the two clamping members together to securely clamp the spherical receiver between the clamping members.