there is provided a garnish attachment structure of a vehicle body using one of a roof garnish provided along a side part of a roof of the vehicle body and a window garnish provided along a side part of a window glass as a first garnish , and using the other as a second garnish . the garnishes are attached to a vehicle body members provided in the vehicle body . the garnish attachment structure includes : positioning locking parts that lock an end of the first garnish from an up - and - down direction and an end of the second garnish from a longitudinal forward - and - backward direction to the vehicle body member ; and engaging parts that are provided at an each end of the first garnish and the second garnish and are locked to the positioning locking parts . the engaging parts are locked to the positioning locking parts , and the ends of the first garnish and the second garnish overlap each other whereby the first garnish and the second garnish are attached to the vehicle body members .