A grass collector adapted to be attached to a rear of a riding-type mower for receiving cut grass from a mower unit through a duct, the grass collector comprises a front container section having a rearwardly facing opening and adapted to be attached to the riding-type mower, the front container section carrying a first bottom plate having a substantially horizontal position; and a rear container section supported pivotably about a pivot point located in a rear upper region of the front container section and pivotable between a first position wherein the rear container section substantially covers the opening of the front container section and a second position pivoted from the first position to allow cut grass to fall, the rear container section having a second bottom plate having a substantially horizontal position.