An impact-resistant wrapping system includes a sheetlike wrapping body having a cavity surrounded by a flexible wall member with gas-barrier properties and a gas-generating capsule having at least two types of materials for generating a gas to expand the cavity of the sheetlike wrapping body. The materials are separately sealed by a film and can be mixed with each other upon being depressed. A portion permeable only to the gas is formed in at least a part of the gas-generating capsule, while the gas-generating capsule is accommodated in the cavity of the sheetlike wrapping body.