This study was conducted to improve the cooking speed in multiproduct Japanese cuisine restaurants using a cooking operation simulator. Traditionally, restaurants improve cooking speed through menu and cooking operation simplification because the cooking speed depends strongly on customer satisfaction and productivity. In recent years, customer requirements for restaurant menus have become diverse. A restaurant must evolve the menu and cooking operations to adapt to customer needs. Cooking systems of multiproduct restaurants can produce diverse menus, but the cooking speed is low. They should improve the cooking speed to improve customer satisfaction and productivity.A cooking operation simulation was conducted to improve cooking speed by improving the kitchen layout, cooking machine capacity, and work plans. Simulation results show that cooking speed can improve: 1) working habits of crew chiefs should be changed to improve cooperation; 2) IE and QC should be introduced to resolve problems such as staff fatigue; 3) simulations should be conducted frequently to adapt to changing customer needs and changing contents of orders.