An apparatus for processing a binary video signal carrying information of dots to be printed. The binary video signal is at a relatively higher or lower level for the whole of each bit time to constitute a unit portion of the binary video signal. The unit portion of the binary video signal at one of the levels is representative of one dot. The apparatus includes a first detector for detecting a start of a length of each of those parts of the binary video signal which are at the one level, a second detector connected with the first detector for determining the number of unit portions contained in each part of the video signal, a generator connected with the second detector for producing one or more dot pulses for each part of the video signal, each of the dot pulses having a pulse width smaller than that corresponding to the bit time, the number of the one dot pulses being the same as that of the determined number of unit portions, and a controller connected with the generator for controllably adjusting the pulse width of the dot pulses.