A transfer from a wheelchair to bed is difficult for wheelchair users without assistance. Because they must lift their bodies up and move from a wheelchair to bed by themselves. So transfer without assistants puts a strain on them and associated with a risk of fall. Some lifts or assist systems called transfer aids are developed to help transfer, nevertheless they needs assistance. Lifts need large space to use and it is hard to carry. To attach the transfer aids, wheelchair needs to be modified. The aim of our study is to develop a transfer aid which can be used by a wheelchair user without assistance. This transfer aid can attach to wheelchair without improvement. And it can be carried easily so wheelchair users can use it everywhere. The developed transfer aid has the spread mechanism that users feel trouble-free to spread the transfer aid. Only by the simple motion of two axis, wheelchair users can spread the transfer aid. The developed transfer aid succeeded to users transfer themselves. And users can transfer more safely and quickly because the developed transfer aid are attached firmly to a wheelchair. One user can transfer by cross direction by using developed transfer aid who usually transfers by forward direction.