An endoscope cleaning/disinfecting apparatus for cleaning/disinfecting an endoscope, comprising: a bottle insertion passage having an opening section on a wall surface of an apparatus body and for introducing a chemical bottle with a chemical solution enclosed therein; an unsealing section placed in the bottle insertion passage for unsealing a chemical discharge section of the chemical bottle to form a chemical discharge port in the chemical bottle; a bottle set section placed movably back and forth inside the bottle insertion passage for housing the chemical bottle so that the chemical discharge section faces upward or sideward with respect to a gravity direction; a guide section placed in the bottle insertion passage for restricting an advancing direction of the bottle set section so that the bottle set section moves linearly back and forth in a portion between a first position and a second position, assuming that a position of the bottle set section for laying the chemical bottle on the bottle set section and for extracting the chemical bottle from the bottle set section is defined as the first position, and a position of the bottle set section for unsealing the chemical bottle with the unsealing section is defined as the second position; a first push-up section serving as an obstacle fixed to the bottle insertion passage; and a second push-up section placed in the bottle set section for transferring force to the chemical bottle to push up a first end portion of the chemical bottle so that the chemical discharge port faces downward in the gravity direction, the force being received upon collision with the first push-up section when the bottle set section is caused to advance from the first position to the second position. a bottle insertion passage having an opening section on a wall surface of an apparatus body and for introducing a chemical bottle with a chemical solution enclosed therein; an unsealing section placed in the bottle insertion passage for unsealing a chemical discharge section of the chemical bottle to form a chemical discharge port in the chemical bottle; a bottle set section placed movably back and forth inside the bottle insertion passage for housing the chemical bottle so that the chemical discharge section faces upward or sideward with respect to a gravity direction; a guide section placed in the bottle insertion passage for restricting an advancing direction of the bottle set section so that the bottle set section moves linearly back and forth in a portion between a first position and a second position, assuming that a position of the bottle set section for laying the chemical bottle on the bottle set section and for extracting the chemical bottle from the bottle set section is defined as the first position, and a position of the bottle set section for unsealing the chemical bottle with the unsealing section is defined as the second position; a first push-up section serving as an obstacle fixed to the bottle insertion passage; and a second push-up section placed in the bottle set section for transferring force to the chemical bottle to push up a first end portion of the chemical bottle so that the chemical discharge port faces downward in the gravity direction, the force being received upon collision with the first push-up section when the bottle set section is caused to advance from the first position to the second position.