As the dimensions of micromachine components decrease, the surface area decreases in proportion to the square of the linear decrease while the volume decreases in proportion to the cube power of the linear decrease. Therefore, the gravity and inertia force proportional to the volume are negligible but the influences of the attraction and friction forces proportional to the surface area are predominant in micromachines. This paper describes some examples of applications of micromachine technologies such as a microfactory and a microsatellite and introduces products of MEMS (microelectromechanical systems). The tribological problems in micromachines are then discussed. First, we show that the attraction force increases the friction force and tribological phenomena in a micro scale are different from the macro tribology. Second, we show a reduction of friction force by creating regular asperity arrays. Finally, the relation between the electrostatic charge and friction is discussed.