The invention provides a bicycle distance adjusting device which comprises a supporting rod, a support, rotary shafts and a chain plate. A coupling is arranged in the middle of the chain plate and provided with a rotary disc, the supporting rod is installed on the rotary disc, telescopic rods are arranged on the two sides of the supporting rod, the rotary shafts are arranged at the lower ends of the telescopic rods, and an installation seat is arranged below the rotary shafts and installed in the chain plate; and a sliding groove is formed in the support, the supporting rod is installed in thesupport and penetrates through the support, a clamping edge is arranged at the upper end of the supporting rod and installed in the sliding groove, and the supporting rod can horizontally move in thesupport. The telescopic rods stretch and retract freely, so that the supporting rod moves forward and backward in the support, the rotary disc rotates at the same time, and the distance is adjusted;and in the process, the telescopic rods achieve a front and back locating effect and supply auxiliary force to the supporting rod, and the adjusted position is reinforced.