It is an urgent problem to establish a design format for unpainted structures of weathering-proof steel and for painted steel structures exposed to a sea wind, especially for the friction type joint with high strength bolts used in these structures. One of the difficulties involved in this problem is due to the time-dependent properties of the structural joint caused by corrosion. In the present study, to obtain the basic data for design of corroded bolted joints, the static and fatigue tests were performed on the corroded specimens of three types of steel SS41, SM50 and SMA50. The results obtained show that the mean value of the slip coefficients of the joints for each type of steel descended slightly with a trend of increasing scattering for longer corrosion period. As for the S-N curve of the specimen composed of steel plate SS41 in which fatigue crack started through the net section, the slope increased after corrosion, and the fatigue strength for 2×106 stress cycles decreased apparently. Based on these results, the variation of the probability of occurrence of slip of the friction type joints were analysed for the cases for which the bolts were clamped by different methods and the joints were corroded acceleratively at various rates.