The invention relates to a reinforcing bar for mineral building materials, particularly for cement. The inventive reinforcing bar (10) is made of a bar of plastic material reinforced by fiber, which has a central, elongate core (12) and several ribs (14) which extend along the length of the core, which are disposed at an angular distance from each other, which form a cross or a star in the cross section thereof and which are twisted around the core axis (16) in a helical manner.