An attachment for an endoscope includes: a tubular main body having a proximal end portion a partition part provided in the main body, the partition part being provided at a position at which a distance from the proximal. end portion to the partition part is longer than a protrusion length of a distal end portion of a device in contact with the partition part toward a proximal end side of the main body, to prevent the distal end portion of the device entering from a distal end side of the main body from coming into contact with a distal end surface of the insertion part and a communication part provided in the partition part, the communication part forming a communication passage through which a proximal end side and a distal end side of the partition part communicate with each other in the main body.
