An electronic apparatus has: a housing with a surface partially formed by a removably attachable lid; and a main-body connector disposed adjacent to an opening to be covered by the lid. A hard disk unit is removably inserted into the opening of the housing of the electronic apparatus. The hard disk unit has a unit connector to be mated with the main body connector. The hard disk unit includes an insulation sheet disposed between a circuit board and a support fitting. A part of the insulation sheet is extended and bent to spread on the rear surface of the support fitting so that connection between the connectors can be released when the extended part of the insulation sheet is pulled.