Provided is a control system of an all-solid-state lithium ion battery which is capable of improving safety. The control system of an all-solid-state lithium ion battery installed in a vehicle includes: an all-solid-state lithium ion battery connected to a motor for driving a vehicle; and a control unit controlling input and output of a current to the all-solid-state lithium ion battery, wherein the all-solid-state lithium ion battery includes an anode containing lithium titanate, and the control unit adds the number of seconds or a current value whenever the charged capacity of the all-solid-state lithium ion battery exceeds 100% of SOC due to an overcurrent, calculates the decreased amount of the SOC limit based on a value obtained from the addition, calculates the second specified SOC based on the decreased amount of the SOC limit, and controls the all-solid-state lithium ion battery based on the second specified SOC.