Disclosed are an apparatus and a method for quickly and accurately inspecting a droplet on a substrate. An apparatus for inspecting a droplet on a substrate according to an exemplary embodiment of the present disclosure includes: an ultrasonic sensor configured to apply an ultrasonic wave to a droplet on the substrate and detect an ultrasonic wave reflected from the substrate; and a processor configured to acquire a height of the droplet at each position on the substrate on the basis of a signal of the ultrasonic wave reflected from the droplet on the substrate, calculate a volume of the droplet on the basis of the heights of the droplet at the positions, and store or output data in relation to the volume of the droplet. The embodiment of the present disclosure may calculate the volume of the droplet using the ultrasonic wave, thereby quickly and accurately inspecting the droplet on the substrate.