  The prospects for the measurement of the pseudoscalar admixture in the
h-tau-tau coupling to a Standard Model Higgs boson of 120 GeV mass are
discussed in a quantitative manner e+ e- collisions of 350 GeV centre-of-mass
energy. Specific angular distributions in the h --> tau tau; tau --> rho nu
decay chain can be used to probe mixing angles of scalar--pseudoscalar
h-tau-tau couplings. In the discussion of the feasibility of the method,
assumptions on the properties of a future detector for an e+ e- linear collider
such as TESLA are used. The Standard Model Higgsstrahlung production process is
taken as an example. For the expected performance of a typical Linear Collider
set-up, the sensitivity of a measurement of the scalar--pseudoscalar mixing
angle turned out to be 6 degree. It will be straightforward to apply our
results to estimate the sensitivity of a measurement, in cases another scenario
of the Higgs boson sector (Standard Model or not) is chosen by nature. The
experimental error of the method is expected to be limited by the statistics.
