Abstract: A musical sound producing apparatus includes a plurality of keys, a sound production information generator that generates sound production information for producing a musical sound based on a first key operation on any key among the plurality of keys, a control information generator that generates control information for controlling, on the basis of a second key operation different from the first key operation, a mode of the musical sound produced on the basis of the first key operation, and a musical sound signal generator that generates a musical sound signal on the basis of the sound production information and the control information.