We have to reduce the electric energy consumed by servers in a cluster. In our previous studies, types of algorithms to select an energy-efficient server for a request process are proposed. Furthermore, schemes for energy-efficiently migrating a process and replicas of a process are discussed where a process and a replica migrate on a host server to a more energy-efficient guest server in our previous studies. However, it is not easy to realize the migration of processes on types of servers. Virtual machine (VM) technologies are now widely used to support applications with virtual resource service in could computing systems. Here, a virtual machine with application processes can migrate from a host server to another guest server. In this paper, we newly propose an energy-aware migration scheme of virtual machines (EAMV). Here, processes on a virtual machine can migrate to a server which consumes smaller electric energy and can be energy-efficiently performed in a cluster. We implement the EAMV scheme and evaluate the migration scheme in terms of energy consumption of servers and execution time of each process.