The objective of our research is to develop the Subgrid-Scale (SGS) model in which external force is explicitly considered and to examine its validity in an actual numerical simulation. To begin with, we derived transport equations of SGS stress and scalar flux with external force following the generalized filtering operation proposed by Germano. Then on the assumption that the production term including the effect of external force was dominant among other terms, the proposed models were obtained as the product of the time scale to the production term. A model parameter included in the proposed models was determined by the dynamic procedure proposed by Germano et al. The proposed models are applied to the simulation of two types of flow with external force having the same geometry: one is the unsteady stratified and the other is the rotating turbulent channel flow. The predicted results of the proposed model shows better agreement with DNS data than the model without the effect of external force.