A lashing device includes: a base seat having a bottom wall, and two pivot lugs which cooperate with the bottom wall to define a pivot slot thereamong, and each of which is formed with an pivot hole communicating with the pivot slot; a pivot pin extending through the pivot hole of each of the pivot lugs; and an eye plate received in the pivot slot, and having a middle portion that is formed with a pivot hole provided for the pivot pin to movably extends therethrough, and first and second wing portions which are connected to opposite ends of the middle portion, respectively, and each of which has an elongated hole having an arc section. The arc axes of the arc sections of the elongated holes are aligned with the center axis of the pivot hole.