Abstract: A data input apparatus comprises an operation panel; a plurality of input keys arranged on the operation panel; and a fine adjusting bar arranged on the operation panel; and a data generator coupled to the input keys and to the fine adjusting bar. Each of the input keys designates a coarse selection of an input instruction, respectively, from among a plurality of input instructions such as musical note pitches and durations. The fine adjusting bar designates a fine adjustment for and in common to the respective selected input instructions designated by the input keys. The data generator generates data bearing information formed by the selected input instruction and the fine adjustment. Thus the data input apparatus composes musical performance data for automatic performance by musical tones with adjusted note pitches, note durations, and other note characters.