Various embodiments disclosed herein relate to an antenna device that provides a wireless communication function and an electronic device including the antenna device is provided. The electronic device includes a communication module and an antenna structure electrically connected to the communication module. The antenna structure may include a conductive substrate including a first area and a second area adjacent to the first area a plurality of first slits formed in the first area of the conductive substrate parallel to each other with a first predetermined interval therebetween in a predetermined direction and a plurality of second slits formed in the second area of the conductive substrate at a position corresponding to an inter-slit area between at least some slits among the plurality of first slits.