A mechanical vibration machining method or the like is suitable for allowing a probe to provide vibration to a horn with high efficiency. A horn portion is supported by a first support portion and a second support portion configured as a double-support structure. A first probe unit and a second probe unit are coupled to both ends of the horn portion. The first probe unit and the second probe unit vibrate the horn portion by means of vibration generated by a first generation unit and a second generation unit. The horn portion provides nodal points at which elongation and contraction alternately occur. For example, in a case in which the contact portion is arranged at the center of the horn portion, the second generation unit is oscillated with a phase that is the opposite of that of the first generation unit.