Abstract: A musical score block copy forming apparatus has a musical keyboard (1) having a full-scale key group and a chromatic-scale key group, and a function keyboard (2) having function keys, and the like. Data input at the keyboards (1, 2) and data necessary for a musical score forming arithmetic operation are stored in a storage unit (7). The input data and the data stored in the storage unit (7) are subjected to arithmetic processing by an arithmetic processing unit (3). The arithmetic processing unit (3) has a layout change function used when a musical score is formed, and can display a musical score on a display (4) on the basis of an arithmetic result. The musical score displayed on the display is output to an output unit (5) for forming a block copy of the musical score.