A storage apparatus and a storing method are provided. The storage apparatus includes one or more storage devices, an interface expander and a master controller. The storage device includes a storage module, a storage control circuit and a ready/busy pin. The storage control circuit outputs an operation status signal according to an operation status of the storage module through the ready/busy pin. The master controller outputs an interface signal to require the interface expander to provide the operation status signal. The interface expander detects the ready/busy pin of the storage device to receive and then transmit the operation status signal from the storage device according to the interface signal and then transmit it to the master controller. The master controller determines whether the storage device is in a busy state or a ready state according to the operation status signal, and accordingly outputs a control signal to control an operation of the storage device.