The invention concerns a channel element (1) for roadway drainage gutter, consisting of a thermoplastic trench body (2) with U-shaped cross-section whereof the horizontal upper ends of the branches (2a) are designed to receive a metallic rabbet (3) for receiving and maintaining a metal grate (4) fixed to the channel body (2) with fixing means such as a screw (9)/nut (10), the trench body (2) including at least a bore (6) arranged at the horizontal upper ends of its branches (2a) to be aligned with matching orifices (7, 8) provided respectively in the rabbet (3) and in the grid (4) for receiving, preferably with clearance, a screw for fixing (9) the grid. Another bore (11) of smaller diameter than the diameter of the screw (9) is provided beneath said housing.