Device assisting with interception by an aircraft of a flight path segment located in a horizontal plane and a system of assistance with interception and follow-up of such a segment.The device includes means of determining a ground speed vector and means of displaying to present, on a screen, a means of indication (10) of the ground speed corresponding to a first rectilinear section (10) in the horizontal plane, connected to a symbol (7) whose angular orientation corresponds to the direction of said ground speed vector and whose length is variable, a means of interception approach indication (12) corresponding to a second recipient section (3) in the horizontal plane of variable width and provided for as an extension of first rectilinear section (11) and a means of indication (14) of the interception turn corresponding to at least one circle arc (15) in the horizontal plane, provided to extend second rectilinear section (13).