Abstract: A keyboard is capable of being used by splitting it in plural key areas at a predetermined split position or positions. A tone forming circuit generates a tone signal corresponding to a depressed key in each key area in a tone generation manner corresponding to one of the split key areas. A plurality of key touch sensors are provided in correspondence to splittable key areas. In case that a certain key split mode is being selected, each touch sensor outputs a touch signal representing a degree of depression of the depressed key in a corresponding key area and supplies it to the tone forming circuit. The tone forming circuit imparts the tone signal for each key area with a touch responsive characteristic in accordance with the corresponding touch signal, thereby performing a properer touch response control in an electronic musical instrument.