In this paper, we present an integrated dual-mode ultrasonic probe that is capable of transmitting and receiving longitudinal and shear waves (LW and SW, respectively) simultaneously. The probe consists of a thick piezoelectric film LW ultrasonic transducer and a substrate with a specific shape. An SW is generated inside the substrate by mode conversion. In the probe design, two factors were theoretically investigated: impedance matching between the substrate and the material being measured to improve measurement sensitivity and mode conversion efficiency at the slanted face of the substrate. The developed probe was tested with a selected silicone liquid sample to demonstrate its capability to measure the properties of a viscous liquid using both LW and SW.