A protective case for protecting a portable electronic device is provided. The case includes first and second bodies which cover the periphery of the electronic device, and locking parts which separably couple the first and second bodies to each other. Each body includes a lateral extension part which extends in a lateral direction, and longitudinal extension parts which extend in a longitudinal direction. The longitudinal extension parts include a longitudinal short side part which extends from an end of the lateral extension part, and a longitudinal long side part which extends from the other end of the lateral extension part. The locking parts are formed at junctions between the longitudinal long side part of the first body and the longitudinal short side part of the second body and between the longitudinal long side part of the second body and the longitudinal short side part of the first body.