An electronic device includes a first antenna that transmits/receives a signal in a first frequency band, a second antenna that transmits/receives a signal in a second frequency band, a first wireless communication circuit connected with the first antenna, a second wireless communication circuit connected with the second antenna, at least one processor connected with the first and second wireless communication circuits, and a memory. The memory stores instructions that cause the processor to output a first signal with a first power to control the first wireless communication circuit to output the first signal through the first antenna, and output the first signal with a power, which is obtained by backing off from the first power as much as a first backoff value, to control the second wireless communication circuit to output a second signal through the second antenna while controlling the first wireless communication circuit to output the first signal.