Abstract: In a static micromixer which comprises at least one mixing chamber and one guide component disposed upstream of the mixing chamber and which includes channels extending therethrough at an angle to the longitudinal axis of the micromixer, so that the channels of alternate layers intersect without communicating with each other, the cross-section of the channels decreases steadily from the entrance end to the exit end of the guide component so as to reduce the pressure losses of the fluid flowing through the channels for mixing in the mixing chamber.