To assist the detachment of a detachable unit flooring member (floor glass etc.) of a building floor.

This mechanism for assisting the detachment of the floor glass 3 placed on a seat portion 2 of a lower portion of an inner edge of a supporting frame comprises a push-up mechanism for pushing up the front side of the floor glass 3 which is placed on the seat portion 2, a sliding leg which is suspended from the rear of each of both lateral sides of the floor glass 3, and a storage recess for housing the sliding leg, which is constituted on the seat portion 2. The push-up mechanism comprises a push-up portion 5 and an ascent/descent operation portion 6. The push-up portion 5 comprises a roller member 5a which is arranged along the front side of the floor glass 3, a roller supporting member 5b for supporting the roller member 5a, a guide mechanism 5c for guiding the ascent/descent of the roller supporting member 5b, a coiled spring 5d for urging the roller supporting member 5b upward, and a lever member 5e which is journaled to push up the roller supporting member 5b by a roller 5e1 for a point of action. The ascent/descent operation portion 6 is composed of an operating wire 6a which acts on a roller 5e3 for a power point so as to lift and rotate the roller 5e1 of the lever member 5e, and a locking piece for locking the operating wire 6a at an end of its extended section.