A mucous membrane lifting instrument for an endoscope includes a lifting portion which protrudes from a distal end portion of an endoscope and includes a push-up surface having a predetermined width so as to lift tissue, a first support portion which is provided at a position protruded from the distal end portion of the endoscope and to be outwardly spaced from an outer circumference surface of the lifting portion with a gap therebetween, and a second support portion which is provided at a position protruded from the distal end portion of the endoscope and to be outwardly spaced from the outer circumference surface of the lifting portion with a gap therebetween, the second support portion being provided to face the first support portion with respect to the lifting portion, wherein each of the first support portion and the second support portion includes a push-down surface having a predetermined width so as to push down peripheral tissue of the tissue pushed up by the push-up surface of the lifting portion.