In the production of semiconductors it is necessary to inspect circuit patterns on wafers. In circuits having very small details (for example, 40 nm), inspection can be carried out by means of electron beam columns, a plurality of wafers then being inspected at the same time and the signals being compared on-line. In an inspection apparatus in accordance with the invention more beam columns 1 to 7 are provided for every wafer A, B, C in order to obtain a high feed-through rate. The inspection is carried out by way of an x-y scan and the wafers are fed through according to a rectilinear movement, thus providing the possibility of scanning only the Care Area Fraction of the wafers, resulting in a high feed-through rate for the wafers in the inspection apparatus.