A transmission apparatus switches to a line of one standby system upon occurrence of a fault on any one of n lines of a working system. The transmission apparatus includes a switching controller that when switching from a line of the working system to a line of the standby-system upon the occurrence of the fault and executing a given command to put the line causing the fault in a given state of line switching according to the given command, causes the working system to maintain the state of line switching according to the given command even after restoration from the fault.