an endoscope to be held by operator's hands and including,

an elongated endoscope housing having a distal end and a proximal end;

an endoscope handle affixed at said housing proximal end;

at least one optical channel designed for visualization of patient's internal organs, extending along said housing from said housing proximal end to said housing distal end, and having a distal optical surface at the distal end of said optical channel;

a cleaning system designed for cleaning said optical surface and comprising a pressurized gas supply channel which extends along said housing and has an inlet port connected with a pressurized gas source, as well as at least one outlet nozzle disposed at said housing distal end and directed towards said optical surface so that a gas jet going out of said nozzle touches said optical surface providing its cleanness, wherein

the pressure value of gas supplied to said nozzle is sufficient to convert said gas jet into a high pressure gas jet capable of completely cleaning said optical surface of any patient's secretions and fog, thereby enabling said gas jet to be a single means for cleaning said optical surface,

a safety means preventing the patient internal organs from barotraumas by said gas jet going out of said nozzle, wherein

all components of said cleaning system and said safety means are disposed inside of said endoscope, with the exception of said pressurized gas source.