An endoscopic instrument cleaning apparatus includes a syringe coupled to a flushing chamber by a form-fitting stopper. A distal, or instrument receiving end of the flushing chamber is inserted into a supply of cleaning fluid and the plunger of the syringe is drawn out to its fully retracted length, thereby filling the syringe and the flushing chamber with cleaning fluid. Then the distal end of an endoscopic instrument is inserted about through an aperture in a stopper having the shape of a conical frustum and is inserted into the flushing chamber to a depth of about 4 inches (10 cm) and the plunger of the syringe is thrust forward to inject pressurized cleaning solution through the endoscopic instrument. In another embodiment, the syringe receiving stopper is recessed within a proximal end of the flush chamber by about 3/8 inches (0.95-1.00 cm) and a tightly fitting tubular insert is glued into the recess to eliminate the possibility that the syringe receiving stopper will be blown out of the flushing chamber by fluid pressure when it is used. Alternatively, an inward projecting lip is formed in the distal end of the flush chamber for the same purpose. A rectangular flushing board includes a neck having a pair of aligned yokes for seating and holding the syringe body to eliminate wrist and thumb strain. In another embodiment, a flushing chamber is formed as an extension to the body of a syringe, thereby eliminating the need for a separate flushing chamber.