Atmospheric trace gases CO, O3, and SO2 were observed at the summit of Mt. Fuji (3776 m a.s.l.) during the summer of 2013. Considerable variations were observed in the concentrations of CO and O3; however, they were correlated in most cases. Trends analyzed through backward trajectory calculations showed lower concentrations of CO and O3 transported from the Pacific Ocean and South East Asia directions, while higher concentrations were detected from the direction of the Asian continent. High O3 and low CO concentrations were observed during some periods; in these air masses, water content of the air was low indicating that the air originated from high altitudes and was influenced by the stratosphere. Gaseous SO2 was mostly lower than the detection limit of the instrument used for measurement (0.06 ppbv), but on August 20–21, high SO2 spikes of about 5 ppbv were observed. Backward and forward trajectory calculations confirmed that volcanic smoke from the Sakurajima volcano was transported to the summit of Mt. Fuji.