The present disclosure provides a bra with adjustable built-in cup spacing, and relates to the technical field of underwear products. The bra includes a cup main body and a bottom, wherein two built-in cups are arranged in the cup main body, the bottom is an elastic telescopic structure, the bottom is fixedly provided with a rotary button between the two built-in cups, and the rotary button is connected to the two built-in cups in respective through a rope. The technical solution solves the technical problem of poor effects of wearing comfort and stability adjustment when a bra capable of adjusting the size and tightness in the prior art is worn.