Background Laryngeal mask is an apparatus for ventilation with efficiency and complexity between tracheal intubation and face mask. It has been frequently used in respiration management. The criteria to determine the timing to remove laryngeal mask but assuring smooth postoperative recovery has not yet been established.　Objective　To discuss factors affecting the timing for laryngeal mask removal.　Content　Successful laryngeal mask removal with the optimal timing should achieve smooth postoperative rehabilitation and avoid adverse effects, such as, bucking, branchial spasm, airway obtrusion, etc. To fulfill this goal, practitioners should systemically evaluate the situation of the patients, such as, age, target control infusion of anesthetics, end?蛳tidal concentrations of inhalation anesthetics, postures, BIS scores, and PETCO2, as well.　Trend　In patients without airway difficulty or airway surgery, laryngeal mask removal should be performed when patients regain automatic respiration, but are still anesthetized.