Video streaming service is offered by various content provider with cloud content delivery network like a Netflix, Youtube. In this environment, for content deliver, cache servers need to be placed properly in cost-effective manner with guaranteeing streaming performance. In this paper, as contents providers, to minimize the cost of using public cloud and to maximize performance of video streaming service, we suggest cost-effective VM offloading algorithm in hybrid cloud environment (CVOH). The CVOH considers performance degradation in internal cloud and cost for public cloud using penalty cost model and learning curve model, respectively. As the result of evaluation for CVOH, we got about twice better performance than a maximal consolidation case, and 9.1 % better than a maximal offloading case.