Recently, the engineering cost of embedded systems is rapidly increasing due to growing sophistication of services. To deal with the problem, hybrid operating system environments have been proposed. This enables to run a RTOS and a general purpose OS concurrently and to reuse software resources on both of them. This approach is efficient in reducing engineering costs. We reconfigured the requirement for these hybrid operating system environment and build a new architecture which fulfills these requirements by using virtualization techniques. Our system provides the facilities to build multiple operating system environment easily. There are two contributions in our systems. One is that the modification cost of the guest OS is small. The second contribution is improvement in system availability by enabling guest OS to reboot independently. Although we used virtualization layer to construct a hybrid operating system environment, the performance overhead is considering small. Therefor our approach is very practical and efficient for recent sophisticated embedded systems.