A swing sprinkler includes a main body, a driving unit, a cover body, an inner plate and an action unit. The tightness of a resilient unit can be adjusted by the user through the action unit, and a secured positioning is formed by the engagement of restricting protruding ribs of the inner plate and positioning protruding ribs of the receiving space to prevent the resilient unit from rewinding after adjustment to effectively adjust the tightness of the resilient unit and swing unit, and increase variability, as well as practicability and convenience of the sprinkler.