A bicycle cable structure is provided with an inner cable, a first outer case, a second outer case and an adjustment structure. The first and second outer cases are disposed over first and second sections of the inner cable and the adjustment structure is disposed between adjacent ends of the first and second outer cases. The adjustment structure includes a main body and an operating member. The operating member is movably connected to the main body by a non-slidable connection between a first position and a second position. The operating member maintains the adjacent ends of the first and second outer cases farther away from each other while the operating member is in the first position as compared to the second position of the operating member.