In one embodiment, a dust collecting apparatus includes a container configured to contain a fluid that includes particles to be collected. The apparatus further includes one or more sound sources configured to generate, in the container, a standing sound wave including at least one node to trap the particles in a vicinity of the node. The one or more sound sources are configured to generate the standing sound wave so that the node does not contact a wall face of the container or contacts a predetermined portion of the wall face of the container. The predetermined portion is formed of a member that prevents the particles from leaving from the node located in a vicinity of the predetermined portion.