The reusability problems in the existing object-oriented development method and component development method is the problem that should be also resolved in the mobile development. Changing the function in mobile applications need to upgrade the entire mobile application, which can cause problems in mobile application in conjunction with other applications within the device. Thus, the changable functions in mobile application should be developed by considering their reusability. In this paper, we propose the customization technique that can be improved reusability for a variety of requirements of mobile application. We propose the self-adaptable customization technique that can change dynamically for the function to require changes by applying the data variability among variabilities.