To provide a linearly moving device in which even if a linearly moving shaft 4 is subjected to load in association with its linear motion, the rotational deflection of a rotating shaft 3 is infallibly prevented on its basal portion and an intermediary region formed between a bearing member 6 and a bearing section 33 is defined as a mobile stroke region where the basal portion of the linearly moving shaft is not guided in a sliding contact manner to enable a back and forth motion of the linearly moving shaft and to make it possible to circumvent such a failure as a thrust decrease attributable to slide friction resistant surface formed over an entire threadably engaging portion.

With the linearly moving shaft 4 guided by a bearing on a wide bearing member 6, the linearly moving shaft 4 is threadably transferred by means of a rotating shaft 3 restricted in its rotational deflection in a threadably engaging zone spreading to an interior region of the bearing member 6. Then, with the basal side of the linearly moving shaft 4 not supported on the bearing, the linearly moving shaft 4 is enabled to move back and forth with the intermediary region defined as the mobile stroke region.

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