Provided is a navigation signal transmitter capable of ensuring reduction in frequency deviation of a terrestrially transmitted navigation signal at low cost. The navigation signal transmitter is operable to receive a transmission wave, generate a synchronization pulse in synchronization with a predetermined data frame, generate an internal clock fundamental oscillation by a reference signal synchronizing section (550) using the synchronization pulse as a reference signal, generate an IMES signal based on the internal clock fundamental oscillation, and transmit the IMES signal. The reference signal synchronizing section (550) comprises a counter circuit (551), a comparator (553), a low-pass control filter (554), a D/A converter (555) and a voltage controlled oscillator (556). The reference signal synchronizing section (550) is configured to, when a magnitude relationship between the number of clock pulses generated in the voltage controlled oscillator (556) using the synchronization pulse as the reference signal and a reference value falls within a predetermined value and continues a predetermined number of times in one direction, adjust a level of control voltage of the voltage controlled oscillator (556).