A key sensor-less automatic player piano includes, key actuators so as to give rise to key motion without any fingering of a human player, key sensors producing key position signals expressing key motion and a data processing unit producing music data codes during a performance on the keyboard and a playback table expressing a relation between the hammer velocity and a reference key velocity; while the data processing unit is recording the performance, the hammer velocity is estimated on the basis of a key velocity-to-hammer velocity conversion table already prepared through an experiment where the keys are depressed by a human player; while the data processing unit is preparing the playback table, the hammer velocity is estimated on the basis of another velocity conversion table prepared through another experiment where the keys are actuated by the key actuators.