The present invention relates to a new configuration, which provides a fixed stair height between all the stairs, by preventing height differences between the lowermost and/or uppermost stairs measurement and the other intermediate stairs due to the fact that the measurement between the floors differ from standard stair measurement in the place where the staircase system is to be located, in staircase systems composed of spines (1) on which stairs are mounted and which are contacted with one another by means of connecting pieces (8); characterized by comprising a clamping piece (2) mounted in the spine (1), which permits stair height adjustment by being tightened and loosened, a connector (5) fixing the said clamping piece (2) into the spine (1), and a washer (4).