The invention relates to a device (1) for holding at least one medical or dental instrument (7) that is fixed to the end of a supply line (9), comprising at least one pivotable lever (3) that is mounted to pivot on a support in a pivoting joint (6) between a rear stand-by position and a front working position on an essentially vertical pivoting plane, extending in an upward manner from the pivoting joint (6) at least in its standby position and curving outwards in its upper region. Said pivoting lever (3) comprises, at least in the region of the curvature (13), one or two limb walls (3e) that extend essentially parallel to the pivotable plane and a line guide (25) for the supply line (9) extending in the longitudinal direction of the curvature (13) in the region of the limb walls. In order to improve said device in relation to a low-friction line guide, said line guide (25) comprises at least one guide roll (27) for the supply line (9).