An apparatus for conditioning plastic containers for putting them into use, in particular ampoules (13), formed into container blocks (11) side by side next to separating lines (17) at which the containers (13) can be separated from one another for use. A pre-separating station (13) is provided, into which the container blocks (11) can be moved in conveying steps and in which a swinging blade (27) is provided for each of the separating lines (17). The swinging blades (27) are coupled to a common drive (31, 33) for a cutting stroke to produce pre-separating incisions at the separating lines (17) such the cutting strokes of each swinging blade (27) takes place in a sequence offset in time in relation to the cutting strokes of other cutting blades (27).