To provide a synchronous tracking circuit where synchronous tracking in the receiving station of a mobile communication system based on a spread spectrum system is executed with superior precision.

The correlation of an early PN(pseudo-noise) code S18e with a late PN code S181 in a receiving signal (in) is calculated in correlative circuits 12a and 12b so as to be outputted as correlative values S12a and S12b. The average of the correlative values S12a and S12b based on a first symbol number is calculated in complex averaging circuits 13a and 13b so as to be outputted as average values S13a and S13b. The absolute values of the average values S13a and S13b are calculated in absolute value circuits 14a and 14b so as to be outputted as absolute values S14a and S14b. The average of the absolute values S14a and S14b based on the second symbol number larger than the first one is calculated in averaging circuits 15a and 15b so as to be outputted as the average values S15a and S15b. The difference value S16 of the average values S15a and S15b is calculated in a difference circuit 16. A timing for outputting the PN codes 18e, 18l and 18m of an PN code generator 18 is changed based on the comparison result of the threshold values (m) and (n) of the difference value S16.