We propose an agent-based simulation model of electricity market incorporating the price-based unit commitment (price-based UC). In the proposed model, an agent owning a set of generating units solves the price-based UC and forms its next-day bidding strategy based on the optimal schedule obtained. The solution approach to the price-based UC is based on Lagrangian relaxation and dynamic programming. This approach gives the optimal schedule based on a forecasted price profile. The simulation results show that each agent can obtain an appropriate next-day bidding strategy by solving the price-based UC.