1. A root-crop planter, comprising: a frame mounted on running wheels; a hopper for the roots fitted on said frame; planting units hingedly secured on said frame under said hopper, each of these units comprising two support wheels longitudinally and transversely offset relative to each other so, that one of the wheels is displaced aside and to the rear, of the other wheel, with regard to the direction of movement of the planter; horizontal links connecting said wheels to one another, and hinged to the rims of the latter so, that the distance between the centers of two adjacent hinges along the rim equals one eighth of the length of the wheel rim circumference; conical planting devices attached to said horizontal links, and each made of two flaps, one of which is hinged to said link, and the other is rigidly fixed to the same link; root knockouts interacting with said planting devices, and secured on said rear support wheel, said horizontal links being made with a two-step deflection, one of said steps forming with the rim of said front support wheel a gap for the passage of said adjacent horizontal link, and said other step forming with the planting device a gap for the passage of said root knockouts, as said two adjacent links are disposed in one horizontal plane; a mechanism to control the lifting and sinking of said planting units, which is attached to said frame of the planter; means to press said planting units to the ground, which are located between the frame of said planting unit and the levers of said mechanism to control the sinking and lifting of the planting units.