In a Mobile Ad hoc Network (MANET), mobile nodes play multiple roles as hosts and routers and are dynamically changing multi-hop structures. MANET consists only of wireless nodes with limit processing power, and routing and data transfer are performed through cooperation with each other. It is exposed to many attack threats due to the dynamic topology by the movement of the nodes and the characteristic of multi-hop communication. Therefore, in MANET, a technique that can detect effectively must be applied while detecting malicious nodes and reducing the impact of various attacks. In this paper, we propose an trust based authentication technique for nodes and a distributed monitoring technique to improve the detection performance of malicious nodes. The hierarchical cluster structure was used to improve authentication of nodes and detection performance and management efficiency of malicious nodes. A lightweight authentication technique of member nodes in the cluster was applied and the efficiency of node authentication was improved. It was used to determine whether it was an attack node by transmitting traffic monitoring information for neighbor nodes to CA and using. In addition, the efficient authentication technique using only key exchange without anyone's help was applied in order to provide integrity when exchanging information between cluster heads. Through this, it was possible to be free from trust information about nodes and forgery and falsification of information about attack nodes. The superiority of the technique proposed in this paper was confirmed through comparative experiments with the existing intrusion detection technique.