Abstract: An all-solid-state battery system according to this application includes an all-solid-state battery and a charging apparatus, in which the all-solid-state battery includes a positive electrode, a negative electrode, and a solid electrolyte layer located between the positive electrode and the negative electrode, the negative electrode contains a negative-electrode active material and a solid electrolyte, the negative-electrode active material contains a lithium titanium oxide, and a negative electrode discharge utilization rate X calculated using the following equation is 134 mAh/g or less. The negative electrode discharge utilization rate X=battery capacity Q (mAh)/mass of the negative-electrode active material in the negative electrode (g), where the battery capacity Q is a discharge capacity (mAh) obtained when the battery is charged with a constant current at 0.2 C to the upper limit charging voltage, charged with a constant voltage to 0.002 C, and discharged at 0.002 C to 1 V.