The invention discloses a waste collecting device which comprises a supporting frame, a first base, a sliding plate and a second base, wherein the supporting frame is vertically arranged, and the first base, the sliding plate and the second base are fixedly connected to the supporting frame successively from bottom to top; a collecting plate is connected to the first base in a sliding manner and can slide on the first base along the first direction; a fixing block is connected to a second sliding block in a sliding manner and can slide on the second sliding block along the first direction, and a gap used for clamping a piece to be processed is formed between the fixing block and the second sliding block; the sliding plate slants down, so that waste in the gap can flow into the collecting plate through the sliding plate. The waste collecting device can prevent the waste from splashing down to harm operators. When the waste collecting device recovers the waste, the waste cannot splash down on the ground and is conveniently cleaned.