  This report describes a measurement of the top quark mass, M_{top}, with the
dynamical likelihood method (DLM) using the CDF II detector at the Fermilab
Tevatron. The Tevatron produces top/anti-top pairs in protons and anti-protons
collisions at a center-of-mass energy of 1.96 TeV. The data sample used in this
analysis was accumulated from March 2002 through August 2004, which corresponds
to an integrated luminosity of 318 pb^{-1}. We use the top/anti-top candidates
in the ``lepton+jets'' decay channel, requiring at least one jet identified as
a b quark by finding a displaced secondary vertex. The DLM defines a likelihood
for each event based on the differential cross section as a function of M_{top}
per unit phase space volume of the final partons, multiplied by the transfer
functions from jet to parton energies. The method takes into account all
possible jet combinations in an event, and the likelihood is multiplied event
by event to derive the top quark mass by the maximum likelihood method. Using
63 top quark candidates observed in the data, with 9.2 events expected from
background, we measure the top quark mass to be 173.2 +2.6/-2.4 (stat.) +/- 3.2
(syst.) GeV/c^2, or 173.2 +4.1/-4.0 GeV/c^2.
