INSULATION RESISTANCE DETECTION APPARATUS

An insulation resistance detection apparatus includes: a first switch connected to a high potential side of a battery assembly including plural battery cells connected in series; a second switch connected to a low potential side of the battery assembly; a detection resistor; a controller configured to turn on one of the first switch and the second switch and turn off the other of the first switch and the second switch to form a series connection circuit including the battery assembly, an insulation resistor of the battery assembly, and the detection resistor, and calculate insulation resistance based on a voltage applied to the detection resistor, in which the first switch is connected between two battery cells on the high potential side among the plural battery cells.