A timepiece gear train structure comprises a center wheel and pinion mounted between a third wheel bridge and a date wheel holder without use of a train wheel bridge as is customarily used in such gear train structures. A plate extends between the third wheel bridge and the date wheel holder and has an opening therein through which extends the intermediate part of the center wheel and pinion thereby rotably supporting the intermediate part thereof. The lower part of the center wheel and pinion is rotatably supported by the date wheel holder by means of a cannon pinion which encircles the lower part, an hour wheel which encircles the cannon pinion and a bush encircling a portion of the hour wheel and being fixed to the date wheel holder.