It is difficult to adopt a simulation technology for simulating a software process because of the difficulty in developing a simulation model. In order to resolve the difficulty, we consider the following issues: reducing the cost to develop a simulation model, reducing the simulation model complexity, and increasing the modularity of a simulation model. We propose an approach to deriving a Discrete Event System Specification (DEVS)-Hybrid simulation model from a Software Process Engineering Metamodel (SPEM)-based software process model. We provide the mapping between the elements of SPEM and the DEVSHybrid formalism and the transformation rules for automatically deriving a simulation model from a descriptive process model. Our approach resolves the issues by the transformation rules and the hierarchical and modularized modeling properties of UML and DEVS.