The objective of the invention is to provide an automatic trading device, an automatic trading system and a paper money exchange trading method. Even if paper money is provided with stains caused by small graffiti, scorch or ink or the like, the paper money can be exchanged. The automatic trading device is characterized in that the device comprises an operating part for prompting a user to select the trading types; a money inputting and outputting part which inputs and outputs paper money in dependence on the selected trading type; a determining part which acquires image information of the input and output paper money and determines the type and the authenticity of the paper money; a first storing bank and a second storing bank which store the determined paper money based on the discrimination results; and a control part. When the burning or pollution level of the input money is higher than a specified value, the control part takes the input money to the first storing bank, and controls the output manner of paper money which is stored in the second storing bank and is in the same type as the input money.