Experimental search for time-reversal violation (T-violation) in heavy meson decays is discussed.. In particular, an experiment E246 which is being prepared at KEK 12-GeV Proton Synchrotron (KEK-PS) to measure the T-violating transverse muon polarization in K+ → π0+μ+υ decay with high sensitivity, is described. Also, possibility of the measurements of the T-violating transverse τ polarization in B semileptonic decays, B → Mτυτ, at future B factories is discussed.