A gastric band of a belt type is presented for attaching around a circumference of a patient's stomach, so as to define the diameter of the stomach opening. The band comprises outer and inner surfaces, wherein the inner surface engages the stomach, and at least the outer surface is formed by an elongated member substantially non-extendable along a longitudinal axis thereof. A through-going opening is made in the elongated member and is located so as to define an end portion of the band having a predetermined length. An opposite end portion of the band is shaped so as to be insertable into the through-going opening for adjusting a desired inner diameter of the band in its closed operating position and fastening the opposite end portion to the outer surface of the band.