To provide a stirrer and an auto-analyzer capable of restraining a piezoelectric substrate or a container from generating heat.

This stirrer/auto-analyzer stirs a liquid held in the container by sound waves. The stirrer 20 is provided with a surface acoustic wave element 23 having the piezoelectric substrate 23b provided in the container 5 and an electrode 23b formed in the piezoelectric substrate, and for generating the sound waves for stirring the liquid, and a sound-absorbing member 24 provided on a face different from a face with the electrode formed in the piezoelectric substrate, or a container outer-wall wall face, and for absorbing one part of sound waves emitted from the surface acoustic wave element.