Insertion instrument and endoscope system

An insertion instrument, comprising:

• an insertion section including a distal end portion, a bending portion, and a flexible tube portion,
• wherein, in a longitudinal direction of the insertion section, the bending portion is between the distal end portion and the flexible tube portion,
• wherein the flexible tube portion is at a proximal end of the insertion section and the distal end portion is at a distal end of the insertion section,
• wherein the distal end portion includes:
• an opening in the distal end portion,
• an objective lens located in the opening, the objective lens including a front surface and a plurality of side surfaces and having a field of view,
• a first conduit extending in the longitudinal direction,
• a second conduit connected to the first conduit, the second conduit extending in a direction other than the longitudinal direction,
• wherein a space between at least one of the plurality of side surfaces of the objective lens and a side surface of the opening defines a third conduit, the third conduit connected to the second conduit, and
• wherein the first conduit, the second conduit and the third conduit form a flow path including a first flow path section located in the first conduit, a second flow path section located in the second conduit, and a third flow path section located in the third conduit.