An electric storage device, comprising: - an electric storage unit including a plurality of electrically connected electric storage elements; - a first control unit configured to measure a state of each of the electric storage elements, wherein the first control unit includes: - a control circuit configured to store each detected inter-terminal voltage of each of the electric storage elements of the electric storage device in a memory circuit; - a measurement unit configured to measure a state of the electric storage unit; and - a second control unit which is configured to capture measurement state information about each of the electric storage elements measured by the first control unit and measurement state information about the electric storage unit measured by the measurement unit, and to manage and to control the state of the electric storage unit, wherein the second control unit includes: a unit which is configured to capture measurement state information about each of the electric storage elements in a no-load state before or after a loaded state where the electric storage unit is connected to a load, and to calculate an amount of change of an average state of charge of the electric storage elements in the no-load state before or after the loaded state, and a difference between an average state of charge of the electric storage elements in a no-load state after the loaded state and a state of charge of a predetermined electric storage element, and which is further configured to calculate a charge-state variation coefficient which is the difference per amount of change of the average state of charge of the electric storage elements in the no-load state before or after the loaded state; and a further unit which is configured to capture the measurement state information about the electric storage unit in the loaded state and calculates an amount of change of the average state of charge of the electric storage elements in the loaded state, and which is further configured to predict a state of charge of a predetermined electric storage element based on the average state of charge of the electric storage elements in the loaded state and the charge-state variation coefficient. - an electric storage unit including a plurality of electrically connected electric storage elements; - a first control unit configured to measure a state of each of the electric storage elements, wherein the first control unit includes: - a control circuit configured to store each detected inter-terminal voltage of each of the electric storage elements of the electric storage device in a memory circuit; - a measurement unit configured to measure a state of the electric storage unit; and - a second control unit which is configured to capture measurement state information about each of the electric storage elements measured by the first control unit and measurement state information about the electric storage unit measured by the measurement unit, and to manage and to control the state of the electric storage unit, wherein the second control unit includes: a unit which is configured to capture measurement state information about each of the electric storage elements in a no-load state before or after a loaded state where the electric storage unit is connected to a load, and to calculate an amount of change of an average state of charge of the electric storage elements in the no-load state before or after the loaded state, and a difference between an average state of charge of the electric storage elements in a no-load state after the loaded state and a state of charge of a predetermined electric storage element, and which is further configured to calculate a charge-state variation coefficient which is the difference per amount of change of the average state of charge of the electric storage elements in the no-load state before or after the loaded state; and a further unit which is configured to capture the measurement state information about the electric storage unit in the loaded state and calculates an amount of change of the average state of charge of the electric storage elements in the loaded state, and which is further configured to predict a state of charge of a predetermined electric storage element based on the average state of charge of the electric storage elements in the loaded state and the charge-state variation coefficient. a unit which is configured to capture measurement state information about each of the electric storage elements in a no-load state before or after a loaded state where the electric storage unit is connected to a load, and to calculate an amount of change of an average state of charge of the electric storage elements in the no-load state before or after the loaded state, and a difference between an average state of charge of the electric storage elements in a no-load state after the loaded state and a state of charge of a predetermined electric storage element, and which is further configured to calculate a charge-state variation coefficient which is the difference per amount of change of the average state of charge of the electric storage elements in the no-load state before or after the loaded state; and a further unit which is configured to capture the measurement state information about the electric storage unit in the loaded state and calculates an amount of change of the average state of charge of the electric storage elements in the loaded state, and which is further configured to predict a state of charge of a predetermined electric storage element based on the average state of charge of the electric storage elements in the loaded state and the charge-state variation coefficient.