First and third counters count an ON time between first and second contact nodes of a key and an ON time between the second contact node and a third contact node, respectively. A second counter counts a time after counting of the first counter is completed. A counter memory stores velocity counter values representing count times of the first and third counters, and a correction time counter value representing the count time of the second counter. An arrival comparator circuit compares an arrival time value and the correction time counter value. In a case that the velocity count value of the first counter is larger than a threshold value, when the arrival comparator circuit detects that the arrival time value coincides with the correction time counter value, a controller outputs a sound generation instruction including touch information according to the velocity counter value loaded from the counter memory.