Vertebral osteosynthesis equipment is presented. The equipment includes at least one connecting bar having an assembly portion, at least two anchoring members and at least one connecting part of the so-called “side loading” type the assembly portion includes at least one protruding lug situated on the side of one of its ends, and the connecting part has a longitudinal slot emerging in said engagement duct, sized to receive said lug in an adjusted manner, but with the lug being able to slide therein, said connecting part being able to be engaged on said assembly portion beyond that lug.