Mobile application can be defined as an Internet application that fits well in the mobile computing environment. Mobile agent system can supports more efficient execution in the mobile computing environments although its environment having wireless network can cause signal disturbance, spurious disconnection by handoff, voluntary disconnection to use power efficiently, and unpredictable transmission error, etc. To act well the mobile application though surrounded by the mobile environmental vulnerabilities, we propose the architecture of mobile agent system. To evaluate the performance of the proposed architecture in a mobile computing environment, we implemented a cyber-market called mobile market agent service (MMAS). In applying the proposed architecture to the MMAS, we found that the mobile agent technique could be suited for the mobile application through the implementation of MMAS, and found out that the proposed architecture could solve the mobile vulnerabilities caused by a mobile computing environment.