An apparatus for forming a thin film pattern according to an aspect of the invention may include: an unwinding roll and a winding roll running a sheet; a rotary drum having an elastic layer provided on a circumferential surface thereof, and disposed between the winding roll and the unwinding roll to run the sheet along the circumferential surface; a source containing unit accommodating a deposition source and mounted such that the deposition source is evaporated and the evaporated deposition source moves toward the sheet located on the rotary drum; a shutter selectively preventing the movement of the deposition source toward the rotary drum from the source containing unit; a mask having a pattern defining a pattern of a thin film to be deposited onto the sheet and making tight contact with the sheet located on the rotary drum during thin-film deposition; and a tensioning unit pressurizing the sheet in a direction of the rotary drum to allow the sheet to run after the thin-film deposition and separating the sheet from the mask by a reduction in thickness.