  We present a measurement of the top quark mass (Mtop) in the all-hadronic
decay channel using 5.8 fb^{-1} of proton-antiproton data collected with the
CDF II detector at the Fermilab Tevatron Collider. Events with 6 to 8 jets are
selected by a neural network algorithm and by the requirement that at least one
of the jets is tagged as a b quark jet. The measurement is performed by a
likelihood fit technique, which determines simultaneously Mtop and the jet
energy scale (JES) calibration. The fit yields a value of 172.5 +- 1.4(stat)
+-1.0(JES) +-1.1(syst) GeV/c^2.
