To keep valuables having different requirements for safekeeping under appropriate conditions by a method wherein an inner cabinet excellent in heat- insulating capacity and an inner safe having a lock and excellent in burglarproofness are provided at the inside of a main safe having a door equipped with a lock.

Slots 7 are provided at liner boards 6 of a main safe 1 in a fireproof/heat-insulating structure having a horizontal swing type door 3 equipped with a cylinder lock 4 and a dial lock 5, and shelves 8 are sustained with brackets held to the slots 7. An inner safe 10, composed of a main body 11 in a heat-insulating structure and a door 12 in a heat-insulating structure equipped with a cylinder lock 13, is placed at the base inside the main body 2 of the main safe 1, and installation is made with an inner cabinet 9 put on top of the inner safe 10. Articles requiring highness in heat insulation and easiness in putting-in and taking-out are housed in the inner cabinet 9 and valuable requiring highness in burglarproofing are housed in the inner safe 10, while articles that can be satisfied with moderate burglarproofness and heat insulation are placed on the shelves 8. Therefore, different kinds of valuables can be appropriately kept in custody without increasing weight for the safe.