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 operational state signal according to an operational state of the storage module through the ready/busy pin. The master controller outputs an interface signal to indicate the interface expander to provide the operational state signal. The interface expander detects the ready/busy pin of the storage device to receive and transmit the operational state signal from the storage device to the master controller according to the interface signal. The master controller determines whether the storage device is in a busy state or a ready state according to the operational state signal, and accordingly outputs a control signal to control operations of the storage devices.