  So far, various Bell type inequalities have been introduced to test the local
realism in tripartite systems. In this article we consider a tripartite system
with two measurements in each side and two outputs for each measurement. Then
we will introduce a new bell type inequality for this system and we show that
this inequality is violated by quantum theory with a violation factor and
amount of violation of 3.5 and 2.5 respectively, which exceed those of
available inequalities in both cases. Also we will show that the white noise
tolerance of this new Bell type expression is 0.5, which agrees with the
maximum amount of white noise tolerance of available inequalities up to now.
