could be adjusted to a low frequency i e the type of low suction pressure and high suction flow and if the patient has viscous mucus or rhinolith the electromagnetic pump 20 could be adjusted to a high frequency i e the type of high suction pressure and low suction flow in order to easily draw the viscous mucus or rhinolith out as it could not be supposed that the mucus suction device of this preferred embodiment will be used for drawing the mucus or drawing the viscous mucus and rhinolith when the mucus suction device is produced the oscillator circuit 43 is set to have a low frequency or a medium frequency that the mucus suction device correspondingly has the type of low suction pressure and high suction flow or the type of medium suction pressure and medium suction flow however users could adjust the suction pressure to a higher one u2014 according to their requirements referring to fig1 a frequency converter circuit 40 of a mucus suction device according to a second preferred embodiment of the present invention is illustrated which further comprises a modulation circuit 45 generating a single phase oscillating signal fig2 is a circuit diagram illustrating the frequency converter circuit 40 as shown in fig1 according to the second preferred embodiment of the present invention the n phase stimulus signal and the s phase stimulus signal generated in the bistable circuit 44 are mixed with the single phase oscillating signal respectively to enhance the n phase stimulus signal while balanced with the s phase stimulus signal and to enhance the s phase stimulus signal while balanced with the n phase stimulus signal respectively i e to enhance the magnetic field strength of the n phase of the electromagnetic device 27 while balanced with the magnetic.