Network security is vital to the achievement of safety in modern society. Cyber attacks to the computer networks of companies, schools, and governments sometimes cause serious damage with service stoppage and /or information leak. "Snort" is commonly-used open software which accumulates rules to detect attacks, although processing speed is limited. We have developed high-speed hardware system where multiple pattern matching is performed in parallel by employing non-deterministic automaton, at the same time hardware compaction is achieved by sharing circuit elements all over the applied rules. Our system detects and eliminates attacks at the speed of 10 Gbps with 1,225 rules, setting a new world record. Since the circuit logic is automatically generated from the Snort rules by our developed program and is written to the FPGA (a logic programmable device) of the system, it is very easy to update the system against new kinds of attacks.