A signal generation device includes a memory configured to store instructions and a processor communicatively connected to the memory. The processor is configured to execute the instructions to function as a signal generation unit to generate a sound signal based on key operation data associated with a key operation and a decay control unit to control a decay speed of the sound signal based on pedal operation data. The decay control unit is configured to control the decay speed to a first speed in a case where the pedal operation position is in a first range, and the decay control unit is configured to control the decay speed to a second speed in a case where the pedal operation position is in a second range. A first boundary position between the first and the second ranges is determined based on control information obtained by the key operation.