The present invention refers to vertical roller devices to assist the supply of stems to sugar cane harvester, which are installed on the front side (A) of the harvester, fastened to the row dividers and which work in pairs, with elements on the right and on the left, which can consist of one or more pairs. The devices are designed to continuously propel and to guide the sugar cane stems to the inside of the harvester. The devices with vertical rollers (6) are formed by hydraulic motors (6a), finned cylinders (6b), upper fixing support members (6c) and lower fixing support members (6d). In the case of a single row, the devices are installed in the harvesters in accordance with to (B) and, in the case of two or more rows, in accordance with (C) on the inner faces (2) of the row dividers. The distance between the elements of the respective pairs decreases from the front to the inside of the harvester, guaranteeing continuous directional pressure on the cane mass as the vertical roller devices convey the cut canes towards the inside of the harvester, eliminating the jamming of stems, and maintaining a constant flow in the front part of the harvester and a consequent increase in harvest yield.