The present application is related to reducing the paint left inside the piping of the painting device. More specifically the present application is directed to a painting device that includes: a paint output part for outputting paint towards an object to be painted; a paint piping for the paint to pass through towards the paint output part; and a steel ball provided inside the paint piping; and a paint supply part supplying the paint to the paint piping from a side opposite to the paint output part. After the paint supply part stops supplying of the paint, the steel ball moves inside the paint piping towards the paint output part while the paint output part outputs the paint towards the object to be painted. The first moving fluid causes the steel ball to move inside the paint piping towards the paint output part by pushing the steel ball.