Detailed operations of the apparatus for the stroboscopic observation of periodic phenomena at the region of line frequencies, such as the magnetic domain response, under the scanning electron microscopy are described in this paper. To achieve the stroboscopic observation at such low frequencies, a new line‐sampling technique has been introduced instead of the conventional point‐sampling method. In addition to the line‐sampling stroboscopy, a multiframe operation is also introduced to display the stroboscopic images of different phase values simultaneously. These operations are simply realized by applying the raster separation and the blanking on the display monitor scope under the multiple line‐sampling during the one‐drive period. To demonstrate the ability of this simple apparatus, some results of the stroboscopic observation of magnetic domains in an Fe–Si sample under a 60‐Hz drive field are also presented in this paper.