In the area of building simulation, modeling of occupants can be classified into three ways, (1) a deterministic approach, (2) a stochastic approach, and (3) a cognitive approach. The deterministic approach is most widely applied where occupants are modeled with a fixed schedule only. The probabilistic approach employs a statistical method to predict human behavior. The aforementioned two approaches regard the humans as static objects. To overcome this, a new modeling approach, so-called an agent-based simulation approach, is demonstrated in this work. By adopting the cognitive approach for agent-based simulation, occupants are modeled as agents who interact with their environments and other agents interactively. This study illustrates the difference between the cognitive approach and the deterministic approach, and benefits from agent-based simulation.