To provide an information transmitting device for transmitting information necessary for searching cargoes randomly placed at any positions.

The information transmitting device 7 is mounted on each of cargoes 2 which can be stacked. The device includes a determining means 8 for determining whether the cargoes are in a stacked condition or not, transfer means 9, 10 for transferring information for the cargo at a stacked lower stage to the cargo at a stacked upper stage when the cargoes are determined to be in the stacked condition, and a transmitting means 3 for optically transmitting information for the cargo at a self-stage to a space when the information for the cargo at the lower stage is not transferred, and for integrating the information for the cargo at the lower stage and the information for the cargo at the self-stage with each other and optically transmitting them to a space when the information for the cargo at the lower stage is transferred.