A collection device including: an accommodation part configured to accommodate therein collected adhering substance; and a detection part configured to detect an amount of the adhering substance in the accommodation part and including, a moving member configured to move from a first position to a second position, the accommodation part being capable of accommodating therein the adhering substance when the moving member is arranged at the first position and being full of the adhering substance when the moving member is in the second position, and a restraining member configured to restrain the moving member from moving from the first position to the second position when the moving member is arranged at the first position, and restrain the moving member from moving from the second position to the first position when the moving member is arranged at the second position.