To efficiently discharge surplus treatment liquid apt to stagnate on the loaded face of a slat through outflow holes and the like so as to perform stable conveyance by forming running rail opposed slide parts carved with outflow grooves communicated to the outflow holes on both wings of the back of the flat with many outflow holes distributively arranged thereon.

A connection link 20 meshing with a sprocket is formed on the back of a slat 10, and the connection links 20 are connected to each other through connecting pins 30 to endlessly constitute the links. Many outflow holes 11 penetrating through are dispersedly arranged on the slat 10, and running rail opposed slide parts 13 carved with many outflow grooves 12 communicated to the respective outflow holes 11 are formed on both wings of the back of the slat 10. Hereby, surplus lubricating oil or the like apt to stagnate on the loaded face of the slat 10 is efficiently discharged in the opposite diection to the chain advancing direction through the respective outflow holes 11 and the respective outflow grooves 12. Consequently, surplus lubricating oil or the like does not scatter on the circumference of a conveyor machine base, and carrying performance or sanitariness of a conveyor chain can be improved.