The communication latency is a primary concern for designing Network-on-Chips (NoCs) since it significantly affects the parallel application performance on a many-core computer system. To reduce the communication latency, we propose an on-chip router that (de)compresses the contents of an incoming packet before completing switch arbitration. The compression router thus has no latency penalty for the compression operation, whereas it shortens a packet length that decreases the network injection-and-ejection latency. Evaluation results show that the compression router improves 7.7% of the parallel application performance (IS, CG, FT, and TSP) and 49% of the effective network throughput by 1.8 compression ratio on NoC. The drawback is that the router area and its energy consumption per bit increase by 0.12mm2 and 1.4 times compared to the conventional virtual-channel router.