A tape storage system including two or more tape storage apparatuses each of which has a tape mounted thereon and is provided with a buffer divided in fixed-length segments, and connected to a host that sends multiple data and a synchronization request at a predetermined timing to the tape recording apparatuses, the tape storage system comprising: a first tape storage apparatus connected to the host, receiving the multiple data sent from the host, and, when the segment is accumulated and filled with the data, writing the accumulated data onto a tape; and a second tape storage apparatus connected to the first tape storage apparatus, receiving the multiple data sent from the host via the first tape storage apparatus, and dumping a predetermined number of data accumulated in the segments onto a tape at a timing of receiving the synchronization request; wherein the first tape storage apparatus does not write data in the buffer until at least one segment of the buffer is completely accumulated with data, ignoring the synchronization request corresponding to the data; and when the predetermined number of data accumulated in the segments is to be dumped onto a tape at the timing of the synchronization request, the second tape storage apparatus pads an area of the segments which is unfilled with the data because the segments are not completely accumulated with the data, to write out the data of the segments; wherein a tape on which writing has been performed by the first tape storage apparatus is treated as a regular writing tape to which data accumulated in the segments are written as data sets; and on a tape on which writing has been performed by the second tape storage apparatus, data accumulated in the segments are written as data sets, and the interval between the data sets on the tape reflects the time interval of the synchronization request; wherein the second tape storage apparatus is able to continuously and overwritably use a tape area for the second tape storage apparatus in which data already written in a tape for the first tape storage apparatus is stored; and wherein, if a data writing error occurs in the first tape storage apparatus, and the data has already been written in the second tape storage apparatus, the data writing error is not reported to the host. a first tape storage apparatus connected to the host, receiving the multiple data sent from the host, and, when the segment is accumulated and filled with the data, writing the accumulated data onto a tape; and a second tape storage apparatus connected to the first tape storage apparatus, receiving the multiple data sent from the host via the first tape storage apparatus, and dumping a predetermined number of data accumulated in the segments onto a tape at a timing of receiving the synchronization request; wherein the first tape storage apparatus does not write data in the buffer until at least one segment of the buffer is completely accumulated with data, ignoring the synchronization request corresponding to the data; and when the predetermined number of data accumulated in the segments is to be dumped onto a tape at the timing of the synchronization request, the second tape storage apparatus pads an area of the segments which is unfilled with the data because the segments are not completely accumulated with the data, to write out the data of the segments; wherein a tape on which writing has been performed by the first tape storage apparatus is treated as a regular writing tape to which data accumulated in the segments are written as data sets; and on a tape on which writing has been performed by the second tape storage apparatus, data accumulated in the segments are written as data sets, and the interval between the data sets on the tape reflects the time interval of the synchronization request; wherein the second tape storage apparatus is able to continuously and overwritably use a tape area for the second tape storage apparatus in which data already written in a tape for the first tape storage apparatus is stored; and wherein, if a data writing error occurs in the first tape storage apparatus, and the data has already been written in the second tape storage apparatus, the data writing error is not reported to the host.