a periodic clock output section for outputting a periodic clock having a preset period;

a transmitting section for transmitting as serial data said transmission signal in synchronism with said periodic clock; and

a receiving section for receiving said transmission signal transmitted from said transmitting section,

wherein said receiving section comprises:

a data synchronizing clock generating section for generating, based on sampling data sampled from said transmission signal received from said transmitting section, a data synchronizing clock synchronized with variation of values of said sampling data;

a periodic phase difference detecting section for detecting a phase difference between said periodic clock received from said periodic clock output section and said data synchronizing clock;

a phase variable clock generating section for generating a plurality of phase variable clocks obtained by varying phase of said periodic clock received from said periodic clock output section so that a variable phase difference which is a phase difference between each of said plurality of phase variable clocks and said data synchronizing clock becomes an amount set in advance based on said phase difference, the phase variable clock generating section comprising:

a delay clock generating section for generating a plurality of delay clocks corresponding to bits of sampling data, whose phases are different from each other, by delaying the periodic clock by different times; and

a delaying section for generating said plurality of phase variable clocks corresponding to said plurality of delay clocks by delaying the phase of each of said plurality of delay clocks so that said variable phase difference becomes said amount set in advance; and

a data sampling section for sampling said sampling data from said transmission signal received from said transmitting section by receiving said transmission signal in synchronism with said phase variable clock to feed it to said data synchronizing clock generating section,

wherein the data sampling section generates parallel data by receiving said transmission signal in synchronism with each of said plurality of phase variable clocks corresponding to said plurality of delay clocks generated by said delaying section and outputs said parallel data as said sampling data.