PURPOSE: To easily draw lines of many size varieties by using only one recording pen by a method in which the amounts of ink to be jetted are varied by changing the relative moving speeds of a recording head and a recording paper.

CONSTITUTION: When output signal of CPU 41 is given to a power source control circuit 42, high voltage is applied between a recording pen 24 and a feeding roller 32 by a high-tension power source circuit 43, and a magnetic ink is jetted to the recording paper 21. In this case, in CPU41, the size of lines is judged by a plotter control command signal, a signal to set up speeds is sent out to speed control circuits 44 and 46, and the turning speeds of drive pulse motors 31 and 37 in the axial directions of Y and X through motor drive circuits 45 and 47 for Y and X shafts by the circuits 44 and 46. As a result, the relative speeds of the recording paper 21 and the pen 24 are set up to given values according to the sizes of lines to be given by the plotter control command.