We have been developing all-solid secondary batteries with sulfide-based thin film electrolyte and pellet-type electrodes. This battery has high performance – it has high-rate discharge properties and cycle properties at high temperature. The battery has shown discharge capability of 10 C for 1 min and cycle properties of 90% capacity-1500 cycle at 60 °C, 90% capacity-500 cycle at 80 °C, and 70% capacity-500 cycle at 150 °C. It has been found that thin film electrolyte gives good effect on both high-rate discharge and cycle performance at a high temperature.