By using an infrared laser diode with an oscillating wavelength of 1550 nm, we demonstrated 15 mA bidirectional laser triggering with an amplitude switching ratio of ~78.9 in a two-terminal microdevice based on a vanadium dioxide (VO2) thin film, which was DC-biased at 3.35 V. The VO2-based device has only one conducting layer, i.e., one VO2 patch, which facilitates the use of the triggering laser with a reduced spot diameter. The reduced beam spot can increase the maximum on-state current at the same illumination power, resulting in the improvement of the amplitude switching ratio. A specific bias voltage range enabling the bidirectional laser triggering was experimentally determined from the current-voltage characteristics of the VO2-based device with an electrode separation of 10 µm and a current channel width of 30 µm, which was measured in a current-controlled mode. In a closed-loop circuit constructed by serially connecting a standard resistor, a DC voltage source, and the device, the transient responses of light-triggered currents were also observed for response time analysis.