In a real-time system, it is attractive to use cluster computing system for realizing high performance and high availability. The objectives of the real-time clusters are maximize guarantee ratio and/or minimize the probability of failure to complete task in time. Because task arrivals are usually uneven among the nodes, some nodes may get temporarily overloaded while others are left underloaded or idle, which leads low performance for real-time clusters. Hence, we need a effective load sharing scheme. In this paper, we describe task migration scheme for real-time cluster environment. Our system uses a single address space architecture because of high predictability. Hence, we have adopted Position Independent Code(PIC) to realize task migration. In our scheme, we introduce "migration type", which decides how to migrate a task by timing constraints of task, communication and whether first allocation or not. Using this scheme, any kind of real-time/non real-time task could be transferred without a crisis of deadline miss.