Disclosed is a battery casing, comprising one or more sub-layers as constitutional elements, wherein at least one region selected from the group consisting of a surface of the casing and the sub-layers of the casing is coated partially or totally with a metal having a grain size of 50 nm or less. A battery comprising the same casing is also disclosed. The casing efficiently inhibits degradation of the safety of a battery, caused by internal or external factors, and thus provides a battery with excellent safety.