To provide a device for sealing and inflating a tire and an inflating method which are not based on an aerosol and consequently, do not depend on a pressurizing process.

This new device (10) includes a sealant container (13) which is filled with a sealant composition but does not contain an inner propellant. Besides, the device (10) is not of an aerosol type. When the device (10) is used, it is connected to a flat tire (11) and a pressure source (18) equipped with an external propellant, which passes through the sealant container (13) to inject the sealant composition into the flat tire (11). The punctured hole is sealed by the sealant composition and the flat tire (11) is inflated by the propellant.