Provided is a misalignment determining device having a size thereof in an axial direction being made short. The misalignment determining device includes a case, a dial gauge, a holder portion, a support portion, a pivotal portion, a lever member, and a slide member. The slide member is placed in contact with a stylus of the dial gauge. While the pivotal portion and the lever member are rotated in synchronism with rotation of the holder portion, a pivot amount of the pivotal portion is transmitted to the slide member via the lever member, and based on an amount of movement of the slide member along an axis direction, the dial gauge determines the pivot amount.