An air belt comprising: a folded member being a bag-shaped belt that inflates with gas introduced therein and is folded in a band shape; and mesh webbing covering the folded member of the bag-shaped belt, with at least a portion of the mesh webbing forming an expandable portion that expands at least in the circumferential direction of the bag-shaped belt during the inflation of the bag-shaped belt, wherein at least the expandable portion of the mesh webbing is made of a raschel-knitted material, and wherein the knitted material is arranged such that the extending direction of knot portions of yarn threads corresponds to the longitudinal direction of the air belt, the air belt being characterized in that the air belt includes a large inflated portion that has a relatively large thickness when the bag-shaped belt inflates and a small inflated portion that is smaller in thickness than the large inflated portion when the bag-shaped belt inflates, that the knitted material is arranged for the large inflated portion and the small inflated portion, that the knitted material arranged for the small inflated portion is knitted such that the length of the knot portions thereof is greater than the length of the knot portions of the knitted material arranged for the large inflated portion, thereby making the amount of expansion of the knitted material arranged for the small inflated portion in the circumferential direction of the bag-shaped belt less than the amount of expansion of the knitted material arranged for the large inflated portion in the circumferential direction of the bag-shaped belt, and that the inflation of the bag-shaped belt is restricted by the knitted material in the small inflated portion. a folded member being a bag-shaped belt that inflates with gas introduced therein and is folded in a band shape; and mesh webbing covering the folded member of the bag-shaped belt, with at least a portion of the mesh webbing forming an expandable portion that expands at least in the circumferential direction of the bag-shaped belt during the inflation of the bag-shaped belt, wherein at least the expandable portion of the mesh webbing is made of a raschel-knitted material, and wherein the knitted material is arranged such that the extending direction of knot portions of yarn threads corresponds to the longitudinal direction of the air belt, the air belt being characterized in that the air belt includes a large inflated portion that has a relatively large thickness when the bag-shaped belt inflates and a small inflated portion that is smaller in thickness than the large inflated portion when the bag-shaped belt inflates, that the knitted material is arranged for the large inflated portion and the small inflated portion, that the knitted material arranged for the small inflated portion is knitted such that the length of the knot portions thereof is greater than the length of the knot portions of the knitted material arranged for the large inflated portion, thereby making the amount of expansion of the knitted material arranged for the small inflated portion in the circumferential direction of the bag-shaped belt less than the amount of expansion of the knitted material arranged for the large inflated portion in the circumferential direction of the bag-shaped belt, and that the inflation of the bag-shaped belt is restricted by the knitted material in the small inflated portion.