To provide a parallel signal serial transmitter that has a comparatively short delay time, is easily operated and is able to send a signal stably.

This transmitter is provided with a transmission section 1 that has a clock generating means 11 that generates a reference clock, a synchronizing signal generating means 12 that generates a synchronizing signal, and a separator bit addition parallel serial conversion means 13 that adds the generated synchronizing signal to an input parallel signal 3 and converts the signal 3 into a serial signal, with a reception section 2 that has a clock recovery means 21 that recovers a clock from a received serial signal, a synchronizing signal detection means 22 that detects the synchronizing signal from the serial signal, and a separate bit deletion serial parallel conversion means 23 that converts the serial signal into a parallel signal, and with a serial signal transmission line 4 through which the serial signal is transmitted.