A synchronizing signal control circuit includes: a phase detecting section configured to detect a phase difference between a display synchronizing signal and an input synchronizing signal; an adding section configured to add a set value for setting a synchronization compensation period and the detected phase difference; a synchronization phase correcting section configured to correct the phase of the input synchronizing signal on the basis of the output signal of the adding section; a gate signal generating section configured to generate a gate signal representing the synchronization compensation period based on the display synchronizing signal; a synchronization determining section configured to determine whether the synchronization can be effected, by detecting whether the input synchronizing signal exists within the synchronization compensation period; and a selecting section configured to perform switching to the corrected input synchronizing signal on the basis of the determination result of the synchronization determining section.