A multiphase ejector including a housing space with a first inlet opening, connectable to a first fluid source, a second inlet opening, connectable to a second fluid source, and an outlet opening. A bush inside the housing space includes a channel having a first opening connected to the first inlet opening and a second opening connected to the second inlet opening and the outlet opening. A member inside the space mixes the fluids and demlimits a channel with a first opening connected to the second opening of the channel and to the second inlet opening, and a second opening connected to the outlet opening. A restriction associated with the bush adjusts the flow-rate of the first fluid in the second opening of the channel. The restriction can be moved between a position of an area having a maximum amplitude, and a position of the second opening being blocked.