A video signal output device and method are capable of easily displaying moving images while synchronizing transmission-side data and reception-side data even if video data is asynchronously transferred to the reception side from the transmission side. A video signal output device for receiving video data transmitted from a transmitter in sync with a first clock through a communication unit, storing the video data in a storage unit, reading the video data from the storage unit in sync with a second clock, and displaying moving images on a display unit, includes a synchronization adjustment unit for detecting a video data correction amount in accordance with a reference video data amount in one vertical synchronous period and a video data amount of the second clock in one vertical synchronous period to adjust a predetermined horizontal scanning period in accordance with the video data correction amount. The synchronization adjustment unit may distribute the video data correction amount to a plurality of invalid horizontal scanning periods not contributing to the display of moving images and adjust the plurality of invalid horizontal scanning periods.