A signal bandwidth expanding apparatus configured to expand a bandwidth of an input signal. The apparatus includes: a time acquiring section configured to acquire time information; a priority holding section configured to hold priority information of processes, each process divided from a process of bandwidth expansion; a controller configured to: sequentially perform the processes from a process having a higher priority using the priority information held by the priority holding section, calculate a time taken for the process using the time acquiring section when the process is ended, and control whether or not a next process having a secondary priority is performed according to the time taken for the process; and a frequency balance correcting section configured to change a frequency characteristic of a signal expanded in a bandwidth according to the process performed by the controller.