A transmission structure of a rotary shaft of an electronic lock contains: a drive unit which includes a holding plate, a motor, a worm, and a driven wheel. The holding plate includes an externally threaded portion and a fixing orifice. The driven wheel includes an internally threaded orifice, two protrusions, two flat zones, two arcuate fringes, and a tooth section. The transmission unit includes a guide element, a movable element, a resilient element, a retainer, and an acting element. The guiding element has a central orifice, the movable element has a guiding orifice, and the acting element has a slidable post. The frame includes a defining orifice and is welded with the holding plate. The connection seat is received in the defining orifice and includes a retaining portion. After the connection seat is received in the defining orifice, the retaining portion is engaged with a fastening ring.