Adjustable dark line box

The invention discloses an adjustable dark line box. An outer box and an inner box capable of being movably arranged in the outer box are arranged on the dark line box; the outer box is a box body with an opened end, a locating part is arranged on an inner wall of the outer box; multiple locating holes matched with the locating parts are arranged on the sidewall of the inner box at intervals alonga width direction; when the inner box moves in place, the locating parts fall in the locating holes so as to locate the outer box and the inner box. The outer box and the inner box are arranged on the adjustable dark line box, and the inner box is movably arranged in the outer box, and the width of the line box can be adjusted by moving relative locations of the inner box and the outer box, thereby adjusting the mounting location of the dark line box, and the dark line box is suitable for the mounting of the mounting holes in different sized without raising or thickening the dark line box. Furthermore, the inner box