To provide a loading space structure of a vehicle capable of securing enough draining property with good outer appearance, without giving anxiety to a user.

In this structure, a loading space 20 is formed at the rear part of a vehicle 10 by a cabin rear wall 21, a side face 22 and the like, and a protection plate 22 covering the side face 22 and a loading space tray 40 put on a bottom face are arranged in the loading space 20. A drain path is formed on the loading space tray 40 by grooves 41, 42. 43. The groove 41 formed along the side edge of the loading space tray 40 is covered with the protection plate 30, so as to increase beauty of the loading space and eliminate admission of trash into the groove 41, for securing the drain path.