Disclosed is a method for manufacturing liquid crystal display device which can peel a protective film from a board assembly and mount the board assembly on a backlight unit. The method for manufacturing a liquid crystal display device, comprising steps of: providing an integrated peeling and mounting device having an index rotary unit having a shaft for rotating heads facing in different directions, an alignment calibration unit and a mounting unit; rotating the index rotary unit; calibrating an aligned state of a board assembly and a backlight unit by operating the alignment calibration unit; mounting the board assembly attached to a first head of the index rotary unit on the backlight unit by operating the mounting unit; and peeling a film from the board assembly attached to a second head of the index rotary unit, wherein the steps of peeling the film and mounting the board assembly on the backlight unit are simultaneously performed.