A non-reciprocal gyromagnetic phase shift device for microwave signals is provided. The device has a section of waveguide with at least two stacked chambers in each of which ferrite-containing slabs are arranged opposite one another on top and bottom walls of the stacked chambers along a common axis, in use a magnetic field being applied to the section of waveguide along the common axis along which are positioned the ferrite-containing slabs. The phase shift device proposed may be used in different microwave circuits. For example, it may be combined with a folded magic tee and a 3 dB hybrid coupler in order to form a 4-port differential phase shift circulator.