The main purpose of this study is to identify the factors that affect purchase intention in B2C cooperative buying. The purchase intention is described in terms of participation frequency and total sum of purchasing on cooperative buying. It is very interesting that the influencing factors are not identical when two dependent variables. participation frequency and total sum of purchasing, are used. Residential area, sex, and product variability were selected as key influencing factors for the former case. On the other hand, residential area, price, and product quality were selected as key influencing factors for the latter case. Finally, it is worth while to stress that online community, one of the factors considered, will be a key factor as market of cooperative buying is getting bigger.