To provide an input support system having a function for improving the operability of an input picture or the like in inputting attribute data through a computer network.

The input support system 2 comprises an attribute data storage part 3 for storing attribute data used for the computer network and an attribute data setting picture generation means 4 for generating an attribute data setting picture for displaying or selecting/setting attribute data stored in the attribute data storage part 3. A data management device A makes terminals start an attribute data setting picture through the attribute data input picture displayed on the terminals (a)-(c). The attribute data of an input target are selected/set on the attribute data setting picture started/displayed on the terminal, and the selected/set attribute data are inputted to the attribute data input picture.