An electronic musical instrument has plural keys each capable of designating different tone pitch and touch response. When any key is depressed by player, touch response information is generated in response to touch intensity or depressing pressure of the depressed key. Based on the touch response information, initial-touch response effect or after-touch response effect is applied to a musical tone of depressed key or musical tones of simultaneously depressed keys. The touch response information is corrected such that the generated musical tones will not be heard un-natural. In addition, by controlling the depressing pressure of key, an automatic performance pattern consisting of predetermined accompaniment pattern and rhythm pattern can be designated and changed.