To obtain an electronic shelf tag device and an electronic shelf tag system that can quickly cope with the change in the indicated contents of a shelf tag indicator according to the change in the display positions of commodities and the change in data of commodity information and the like stored in an external apparatus.

The information on display positions for specifying each display position 2b set by a dip switch 10 that is a positional information specifying means is fixed regardless of attaching or detaching an indicator 7, and commodity information D indicated by the indicator 7 is stored in a nonvolatile storage medium provided in the indicator 7. Thus, only replacing the indicator 7 according to the changed display position 2b of commodities is necessary in the case of changing the display position of the commodities urgently, for example, at the salesroom of a super market and the like, so the change in the indicated contents of the indicator 7 according to the change in the display positions of the commodities and the change in data of the commodity information and the like stored in an external apparatus can be dealt with quickly.