A device for inflating a tire having gone flat to a wanted pressure and for sealing and inflating a puncture tire. The device includes a compressed-air source, a tubular container filled with a sealing agent, and a first conduit having an adapter at its second end for connecting the conduit to a valve on the tire. The container furthermore has an inlet opening for passage of compressed air from the compressed-air source and an outlet opening for passage of sealing agent. The container is enclosed by a tubular cylinder having at one end an aperture closed by a cover. The cover is mounted displaceable on the cylinder between a first operative position and a second operative position. Thereby, it is obtained that the device is quick and easy to operate. Sealing and inflating of a puncture tire are done in between one and three minutes. Packed up, the device takes up practically no space whereby the heavy and bulky spare wheel is made unnecessary. Thereby, the space and load capacity previously occupied by the spare wheel is utilized.