A vehicle body has, in a state in which a battery unit is not installed, a frame configuring a part of the lower surface of the vehicle body. A vehicle battery unit installation apparatus for installing a battery unit in the lower part of the vehicle body includes: a striker device configured to be secured to the vehicle body and a locking device secured to the battery unit. The striker device includes a base plate and a striker secured to the base plate. The striker has a support part capable of supporting a load. The locking device is capable of securing the support part. The base plate is configured to be secured to the frame. The striker has ends secured to the base plate such that the support part is located below the frame.