PURPOSE: To suggest bed liners of a plurality of parts capable of protecting a bed of an automobile and being loaded out in the form of components.

CONSTITUTION: A bed liner includes a panel network and a rail network. The panel network includes relative side surface panels 30, a front surface panel 32, a gate panel 34 and a floor panel 36. Panels are separate one another and can be directly screwed onto a bed of an automobile. The rail network includes relative side surface rails 50, a front surface rail 52, and a gate rail 54. In grooves in the rails, a part of each corresponding panel is accepted.