The aim here in the report is to study and validate how it influences thinking process by introducing the idea-generation method of brainwriting(BW) to the first stage of space designing with the group work. We've set the subject for the space designing and analyzed comparatively. The method of our analysis is based on the data of 2 groups: One is the group which supports the idea of BW. The other is the group which advances the idea freely. The results are following. 1)We've got 5 patterns through the procedures for making proposal document. The 1st group's data showed the pattern to develop their thought in most cases. 2)When we paid attention to the supporting group of BW, the number of language data in one topic and the amount of idea sketch were increased. We've found lots of idea development with sketch even when they make the draft proposal. 3)It was proved that compulsory jumps to abstract thought with BW lead to think developmentally and create better idea.