According to an embodiment, an article posture changing device includes: a first end effector configured to grasp a projected tag of an article by adsorption; an arm unit configured to support the first end effector and move the first end effector along at least a vertical direction; and a controller configured to control the arm unit and the first end effector to grasp the tag, lift the article upward, separate the article from a placement surface, change an angle of the article by weight thereof, move the article downward, place the article on the placement surface, and release the grasp of the tag.