A hinge structure is provided. The hinge structure includes a first rotary member connected with a first housing, a second rotary member connected with a second housing, a gear structure that makes the first rotary member and the second rotary member operate in conjunction with each other, a first arm connected with the first rotary member, a second arm connected with the second rotary member, a first torque providing member that fastens the first arm and the first rotary member, and a second torque providing member that fastens the second arm and the second rotary member.