An attachment structure comprising: a bedclothes fitting instrument fitted to bedclothes; and an instrument, wherein the bedclothes fitting instrument includes a bedclothes fixed portion fixed to the bedclothes, and a first contact portion including a first magnetic element, the instrument includes a second contact portion including a second magnetic element, the bedclothes fitting instrument and the instrument are brought in contact as being rotatable relatively to each other around a magnetic force direction and attachable to and detachable from each other as a result of contact between the first contact portion and the second contact portion by magnetic force of the first magnetic element and the second magnetic element, the bedclothes fitting instrument and the instrument include a movement restriction portion configured to restrict movement of the first contact portion and the second contact portion relative to each other in a direction perpendicular the magnetic force direction while the first contact portion and the second contact portion are brought in contact with each other, and the bedclothes fitting instrument and the instrument include a pivot restriction portion configured to restrict pivot around a side opposite to a side of the bedclothes fixed portion with respect to the first contact portion, more than pivot around the side of the bedclothes fixed portion, when the first contact portion and the second contact portion pivot relatively to each other as moving away from each other in the magnetic force direction from a state that the first contact portion and the second contact portion are brought in contact with each other. a bedclothes fitting instrument fitted to bedclothes; and an instrument, wherein the bedclothes fitting instrument includes a bedclothes fixed portion fixed to the bedclothes, and a first contact portion including a first magnetic element, the instrument includes a second contact portion including a second magnetic element, the bedclothes fitting instrument and the instrument are brought in contact as being rotatable relatively to each other around a magnetic force direction and attachable to and detachable from each other as a result of contact between the first contact portion and the second contact portion by magnetic force of the first magnetic element and the second magnetic element, the bedclothes fitting instrument and the instrument include a movement restriction portion configured to restrict movement of the first contact portion and the second contact portion relative to each other in a direction perpendicular the magnetic force direction while the first contact portion and the second contact portion are brought in contact with each other, and the bedclothes fitting instrument and the instrument include a pivot restriction portion configured to restrict pivot around a side opposite to a side of the bedclothes fixed portion with respect to the first contact portion, more than pivot around the side of the bedclothes fixed portion, when the first contact portion and the second contact portion pivot relatively to each other as moving away from each other in the magnetic force direction from a state that the first contact portion and the second contact portion are brought in contact with each other.