In this study, we observe the time-series of the stress field of a cantilever beam subjected to a dynamic load by using holographic Particle-Tracking Velocimetry (PTV). The beam (elastic modulus 2822 MPa, 3.95×20.45×2.99 mm3) is composed of a transparent acrylic resin containing dispersed tracer particles (average diameter: 60 µm). The cantilever beam is subjected to a dynamic load (0 N to 10 N over 10 sec) at the tip. We compare the experimental and analytical values of the deflection at t = 10 sec. The RMS error is 24.5 µm with respect to the maximum deflection value of 657 µm.