A belt for a continuously variable transmission in which an aggregate of metal rings formed by laminating a plurality of pieces of endless metal rings support a plurality of metal blocks. When the ratio .xi. of the coefficient of friction is set to be 2.0>.xi.>0.65, the amount of change in the tension on the metal ring of the innermost position decreases correspondingly. In particular, when the ratio .xi. of the coefficient of friction is set to be 1.0, resulting in the coefficient of friction .mu..sub.s between a ring and a block being equal to the coefficient of friction .mu..sub.SS between a ring and a ring, the amount of change in the tension on all metal rings become uniform, and each metal ring shares an amount of change in the tension which is 8% of the entire amount. This makes it possible to decrease the amount of change in the tension on the metal ring of the innermost position and, hence, to increase the durability of the aggregate of metal rings as a whole.