To provide a vehicle battery temperature adjusting device and a temperature adjusting method of a vehicle battery, capable of shortening time required up to completing charging from stopping of a vehicle.

This vehicle battery temperature adjusting device includes a battery 1 chargeable in an on-vehicle state by a charging stand 11, a battery temperature sensor 4 for detecting the battery temperature, an SOC estimating part 3a for calculating battery SOC, an air conditioner unit 2 for adjusting the battery temperature, a charging determining part 3b for determining whether or not to be necessary to charge the battery 1 from the battery SOC, and a temperature adjusting part 3c for executing travel time temperature adjusting control for outputting a temperature adjusting control command to the air conditioner unit 2 so that the battery temperature becomes the target temperature when starting charging when determining that the charging is necessary when a vehicle travels.