An automatic performance apparatus which enables expressive ensemble performance to be carried out with a sense of uniformity. Operation signals according to operation by at least one operator, and identification information for identifying a plurality of operating elements are output from these operating elements. Operation-related information indicative of the relationship between respective ones of the plurality of operating elements and respective ones of a plurality of channels, and the master-slave relationship between the plurality of operating elements are stored in a storage. When the operation signals and the identification information are output from the plurality of operating elements, the operation-related information is referred to determine corresponding ones of the channels to the identification information, a sounding event of a musical tone to be sounded next is read out from the performance data for each of the corresponding ones of the channels, and a sounding process on the readout sounding event is carried out by a sounding processing device. The sounding process is controlled such that the position of a sounding event corresponding to at least one of the operating elements as a slave never goes beyond the position of a sounding event corresponding to one of the operating elements as a master, which is to be processed next.