To provide various minute speed reduction mechanisms which have a simple mechanism, are light in weight and compact, and can reduce a speed minutely, that is, can reduce a rotary speed markedly.

Operation faces face each other by aligning shafts of rotation center of an elastic wheel 1 and a rigid body wheel 2, and the wheel on one side is stopped and the other wheel is connected with an output shaft. An equal radius position of an equally divided angle of the elastic wheel 1 is pressed by an indentor 4, and the indentor 4 is rotated and driven to transmit a rotary force to the output shaft. Or, an annular wheel or a cup wheel and a shaftlike wheel are arranged by facing each other, a shape center shaft of either of both wheels is inclined and turned for the other shape center shaft at an attitude where the former is inclined to incline and turn it due to shaft rotation of an input shaft and pressing by the indentor, and the rotation of the wheel on one side is stopped and rotation of the other wheel is taken out as output rotation.