A holder for holding a portable electronic device can be changed between a folded position and an unfolded position. The holder holds the portable electronic device in the folded position. In the unfolded position, the holder has its supporting board, front holding board, rear holding board, side holding boards, bottom holding boards substantially planar with each other. In the folded position, the supporting board supports the side holding boards to vertically stand, the rear holding board is secured above the supporting board at an obtuse angle, and the front holding board is maintained parallel with the rear holding board.