Disclosed herein is a battery pack case. An upper cover, a lower support base and each side cover form at least one seating depression extending in a sideways direction. Each of the front and rear covers has band locking depressions at positions corresponding to the seating depressions. Each band locking depression has a shape corresponding to a related one of fixing bands. Each fixing band includes a band body which is made of rubber, fabric or plastic and extends a predetermined length in one direction, and a locking protrusion provided on each of opposite ends of the band body. The locking protrusion has a structure corresponding to a related one of the band locking depressions. The locking protrusions of the fixing bands are inserted into the corresponding band locking depressions, thus fastening the elements including the front cover and the rear cover together.