To make it possible to operate a guide always in a smooth, stable state without causing deformation of the guide by aligning the direction of a pressuring force of an ultrasonic linear motor to a pre-load direction to a straight-line guide.

By a frictional force corresponding to a pressuring force by a pressuring spring 36, the vibration of an ultrasonic elastic body 34 is propagated to a guide member 31 through a slide member 37 and becomes a thrust. As a result, the guide member 31 has a straight motion relatively to a guide member 32 along V-groove 31a1, 32a1, 31b1, and 32b1. At this time, the pressuring force of a pressuring spring 36 acts as it is to the guide members 31 and 32 as the pre-load in the same direction, and respective balls 33 clamped between V grooves 31a1, 32a1, 31b1, and 32b1 are deformed elastically. Thus, no excessive force is applied to the guide members 31 and 32 and stable straight motion can be realized.