A peripheral connected to a host computer is prevented from unexpectedly coming
to be in a non-connection state due to control of the host computer. Further, even
when the peripheral such as an electronic camera cannot enough receive power necessary
for the device itself from a connection line such as a USB, the peripheral is made
to be able to use the power effectively. To achieve this, there is disclosed a
computer peripheral which is connected to the host computer and comprises a connection
signal transmitter for transmitting to the host computer a signal to control the
connection with the host computer and a controller for shifting an operation state
of the computer peripheral to a low consumption current mode after notifying a
user and obtaining approval of the user before transmitting a signal to control
into the disconnection state to the host computer by the connection signal transmitter.