The compressor includes two compression spaces (1, 5) separate from one another, one of which serves to generate the continuous pressure medium flow for the generation of a basic aerosol flow, whereas the other is used to generate the pressure variations. The shared compression device (4), for example a piston, is moved in a pendulum motion by a drive (7) so that a gas is conveyed through the first compression space and pressure variations are imposed upon a gas volume via the second compression space. The drive is disposed in a compression space, use advantageously being made of the space volume available that may if necessary be made use of by the compressor. In a preferred embodiment the drive (7) is located in the compression space (5) that is used to generate the pressure variations.