A processing device includes a controller including hardware. The controller is configured to execute: generating an ultrasound image based on an ultrasound signal acquired by an ultrasound probe, the ultrasound probe being configured to transmit an ultrasonic wave to a subject that is an observation target and receive an ultrasonic wave reflected by the subject generating shift information including a shift direction of a display area of the ultrasound image displayed on a display unit in accordance with a command position with respect to the ultrasound image shifting the ultrasound image in accordance with the shift information and generating a character image indicating an area targeted for a process performed on the ultrasound image in relation to the command position in the ultrasound image after being shifted.
