To provide a battery pack equalization device with less waste by appropriately performing equalization processing depending on a charge state of the whole battery pack.
A battery pack equalization device 10 for equalizing charge amounts of respective single batteries of a battery (battery pack) 103 composed of the plurality of rechargeable single batteries 103a1 to 103a3 connected in series comprises: a charging rate detection unit 11 for detecting a whole charging rate of the whole battery; a threshold setting unit 12 for setting different charging state thresholds depending on the whole charging rate of the whole battery; an index detection unit 13 for detecting maximum difference voltage showing variation in single charging rates (voltage) of each of the plurality of single batteries; and an equalization control unit 14 which acquires a charging state threshold depending on a whole charging rate, and executes equalization processing of charging rates for each single battery when it is confirmed that the maximum difference voltage has been equal to or more than the charging state threshold.
ITO SATOSHI
MORIKAWA TOMOAKI
