A mobile apparatus comprising: a first body including a keyboard; a second body including a display unit arranged to display an image; a rotary adaptor rotatably installed on the first body, and configured to magnetically attach the first body to the second body; protrusions disposed on one of the rotary adaptor and the second body; and concave portions disposed on the other one of the rotary adaptor and the second body so that the protrusions are configured to be inserted into the concave portions, wherein the rotary adaptor includes an accommodation portion to accommodate a side portion (21, 22) of the second body; wherein the accommodation portion of the rotary adaptor includes a plurality of first magnets and a first electric contact portion disposed between the plurality of first magnets, and the side portion (21,22) of the second body includes a plurality of second magnets to face the plurality of first magnets when the side portion (21, 22) is accommodated in the accommodation portion, and a second electric contact portion disposed between the plurality of second magnets and configured to be in contact with the first electric contact portion when the first body is attached to the second body via the rotary adaptor, wherein the plurality of second magnets comprise at least one magnet having a length longer than a thickness of the side portion (21,22) of the second body, and the plurality of first magnets comprise at least one magnet having a same size as the at least one magnet of the plurality of second magnets, wherein the accommodation portion is configured to allow the second body to move along a direction of a rotational axis of the rotary adaptor such that the protrusions are inserted into the concave portions. a first body including a keyboard; a second body including a display unit arranged to display an image; a rotary adaptor rotatably installed on the first body, and configured to magnetically attach the first body to the second body; protrusions disposed on one of the rotary adaptor and the second body; and concave portions disposed on the other one of the rotary adaptor and the second body so that the protrusions are configured to be inserted into the concave portions, wherein the rotary adaptor includes an accommodation portion to accommodate a side portion (21, 22) of the second body; wherein the accommodation portion of the rotary adaptor includes a plurality of first magnets and a first electric contact portion disposed between the plurality of first magnets, and the side portion (21,22) of the second body includes a plurality of second magnets to face the plurality of first magnets when the side portion (21, 22) is accommodated in the accommodation portion, and a second electric contact portion disposed between the plurality of second magnets and configured to be in contact with the first electric contact portion when the first body is attached to the second body via the rotary adaptor, wherein the plurality of second magnets comprise at least one magnet having a length longer than a thickness of the side portion (21,22) of the second body, and the plurality of first magnets comprise at least one magnet having a same size as the at least one magnet of the plurality of second magnets, wherein the accommodation portion is configured to allow the second body to move along a direction of a rotational axis of the rotary adaptor such that the protrusions are inserted into the concave portions.