A coil device for transmitting wireless power includes at least one switch, a first coil, a second coil configured to be physically connected to the first coil through the at least one switch, a third coil configured to be physically connected to the first coil through the at least one switch, and a logic circuit configured to control the at least one switch. In a first mode, the logic circuit is configured to control the at least one switch so that an inductance of the first coil is a first inductance and control the at least one switch so that the first coil and the second coil are connected to each other and the first coil and the third coil are not connected to each other. In a second mode, the logic circuit is configured to control the at least one switch so that the inductance of the first coil is a second inductance and control the at least one switch so that the first coil and the third coil are connected to each other and the first coil and the second coil are not connected to each other.