An apparatus for mounting bus bars having at least one bus bar holder which can be attached to a loadbearing structure and which has at least one foot receptacle for introducing a foot section of a bus bar and fixing the latter by a holding piece. Simple, stable mounting of bus bars can be achieved if the holding piece is configured as a separate part which can be attached releasably or which is attached releasably to a base part of the bus bar holder and which has a connecting section for attachment to an adapted holding piece receptacle of the base part and a head part which engages over the former for fixing the foot section.