An image forming device includes, the first head which ejects the first ink, the second head which ejects the second ink, a movement mechanism which moves a relative position of the first head and the second head in a predetermined direction, and a control unit which causes an ejection operation in which ink is ejected from nozzles while relatively moving the head and a medium in the movement direction intersecting the predetermined direction, and a transport operation in which the head and the medium are relatively moved in a predetermined direction to be repeated, and adjusts a head interval as an interval of the first head and the second head in a predetermined direction.