To provide a working position determination system of a work vehicle capable of accurately specifying a place where the work vehicle has performed a work.

This working position determination system of a work vehicle includes a position information acquisition device (GPS) for acquiring the position information indicating the present position of the work vehicle having a working device on the deck, a work position information storage for storing a plurality of working position information including the positional range of the working position, and a calculator for selecting one working position based on the position information of the work vehicle and the working position information of the plurality of working position information storage. The positional range is stored differently for each working position.