The decline came as inflation in the country outpaced growth in nominal wages.
The consumer price index excluding imputed rents, used to calculate the real wage index, grew 3.1% in the reporting month. The pace of rise in the price index topped nominal wage growth for the fourth consecutive month.
The average total nominal wage was up 1.8% year on year at ¥377,809 per worker in July, up for seven months in a row, according to the labor survey report.
Of the total, regular pay, including basic salary, rose 1.2%, and overtime and other nonregular pay climbed 4.7%. Special pay, including bonuses, was up 2.8%.
Total nominal wages for full-time workers averaged ¥500,828, up 1.7%, and the average wage for part-time workers grew 3.0% to ¥106,167.