Abstract: A state of charge estimation apparatus that estimates a state of charge of a secondary battery includes a processor and associated memory configured to: obtain a voltage measurement value, a current measurement value, and a temperature measurement value of the second battery; calculate a state of charge estimation value of the secondary battery based on the current measurement value; determine whether or not the voltage measurement value of the secondary battery has reached a predetermined voltage threshold during charge or discharge of the secondary battery; and in a case where the voltage measurement value of the secondary battery is determined to have reached the voltage threshold, correct the state of charge estimation value based on the current measurement value and the temperature measurement value that are obtained at a correction time point at which the voltage measurement value of the secondary battery has reached the voltage threshold.