Since soil and ground water pollution with agricultural chemicals have become very serious problems all over the world, detection of water flow implicating the contaminant flow-vector in the soil has been desired ever before.  Endo and Hara (2003) conducted simultaneous measurement of thermal front advection velocity (TFAV) vector, thermal properties (thermal diffusivity k  [ m² s^-1 ] and volumetric heat capacity rc [ J m^-3 K^-1 ] ) with Quintuple-Probe Heat-Pulse (QPHP) sensor for a water-saturated sand column under steady state conditions.  The QPHP sensor consists of a heater rod at the center and four thermocouple rods around the heater rod as shown in Fig.1.  We measured temporal changes of differences ( DT_1-3 (t) and DT_2-4 (t) ) and sums ( DT₁₊₃ (t) and DT₂₊₄ (t) ) of temperature changes imposing different magnitudes and durations of a heat pulse under steady state water flow conditions.  A normalized flow vector, thermal properties and TFAV were estimated from the measured DT (t) data.  The TFAV was transformed to the water flux density J_w [ m³ m^-2 s^-1 ] using measured rc and introduced volumetric heat capacity of the fluid (rc)_w (Melville et al, 1985), the water flux density J_w was then transformed to pore water velocity V_w(=J_w/q) using introduced volumetric water content q(=(rc  - (rc)₀ ) /(rc)_w).  Here, (rc)₀ is volumetric heat capacity at q=0.  As a result of this experiment, measured J_w and thermal properties were in good agreement with the control values.  In order to verify the utility of QPHP measurement for unsaturated conditions, temporal change of the J_w and thermal properties were also observed in inclined-multiply layered-sand under infiltration conditions.  Fine and coarse textured sands were packed in a transparent infiltration box (W150cmxH80cmxT5cm) in order to achieve 0.03[m³ m^-3] of q and 1.5[Mg m^-3] of bulk density.  Subsequently, QPHP sensors were inserted through a wall of the infiltration box.  Wetting front observations were conducted in 5 to 15 minutes intervals supplying water to a narrow band of the sand surface.  Infiltrated water tended to move downward and along the boundary between finer and coarser layers as a funneled type preferential flow.  Measurements using the QPHP sensors under infiltration were conducted and then J_wx, J_wy, k, rc and q were identified.  The V_w measured with QPHP sensor was in good agreement with the advancing velocity of the wetting front, V_f.  The values of rc and the corresponding q  at sensor positions tended to increase when the wetting front reached.  The V_w identified with QPHP sensors was slightly lower than the V_f (Fig.2).  As a result, the simultaneous measurements of fluid flow vectors and the thermal properties under unsaturated condition in infiltration have been achieved.  In addition, measured values with the QPHP sensors also agreed well with the wetting front observations and gravimetric measurements of water content.