An uncomplicated bicycle device for fastening a steering tube with a stem tube includes two compression rings and a fastening set. The compression ring is fixed on a stem opening by inserting the lateral surface portion into the stem tube and the protruding portion abutted against the stem opening. The steering tube is inserted into the compression rings. A fastening set includes a star nut placed into the steering tube, a cap covering the stem opening and abutted against the compression ring, a cap bolt for screwing the cap and the star nut together. The present invention only uses the compression rings and the fastening set instead of any thread structure and lock nuts for fastening the steering tube within the stem tube. Thus, the adjuster can quickly calibrate and assemble the steering tube within the stem tube again.