  We discuss lepton flavor violation (LFV) associated with tau leptons in the
general framework of the two Higgs doublet model, in which LFV couplings are
introduced as a deviation from Model II Yukawa interaction. Parameters of the
model are constrained from experimental results and also from requirements of
theoretical consistencies such as vacuum stability and perturbative unitarity.
Current data for LFV rare tau decays provide substantial upper limits on the
LFV Yukawa couplings in the large $\tan\beta$ region, which are comparable with
predictions in fundamental theories. Here $\tan\beta$ is the ratio of vacuum
expectation values of the two Higgs doublets. A search for the LFV decays
$\phi^{0} \to \tau^\pm \mu^\mp$ $(\tau^\pm e^\mp)$ of neutral Higgs bosons
($\phi^{0} =h,H$ and $A$) at future collider experiments can be useful to
further constrain the LFV couplings, especially in the relatively small
$\tan\beta$ region ($\tan\beta \lesssim 30 $), where rare tau decay data cannot
give any strong limit.
