PURPOSE: To imitate a spread of pipes with minimum echo adding devices even in the case of an electronic organ made to imitate a pipe organ which produces musical sounds by many sound sources by adding echo after dividing plural sound sources into groups.

CONSTITUTION: A keyboard 1 and a stop switch 2 provided on a console are connected to an assigner 3, and plural (64) sound producing circuits 4 are connected to the assigner 3. Each sound producing circuit 4 consists of a musical sound producing circuit 20 to produce musical sounds, an orientating circuit 21 which orientates a generated musical sound signal to the right and the left two-dimensionally, and a switching circuit 22 to switch which system (echo adding device 5) the musical sound signal is inputted. Plural sound sources are divided into groups, and the acoustic image is orientated in each group, and echo different by group is added, and plural sound sources are divided into groups based on arrangement of pipes (stop) which sound sources imitate. Thus, required minimum echo adding devices 5 are used to imitate the echo of the pipe organ which has pipes arranged in the whole of a building.