An electronic device which can be installed and removed in an apparatus using only one hand includes a base and a positioning member. A positioning opening is formed on a first side surface of the base, and a channel is formed in the base with one end connected to the positioning opening. The positioning member is located in the channel and has a holding groove exposed from a front surface of the base. The positioning member is movable along the channel between a released position and a compressed (mounted) position. In the released position, a locking portion of the positioning member extends out of the channel via the positioning opening, in the compressed position the locking portion is retracted into the channel.