An endoscope cover fixing device able to reliably fix the position of a cover to an endoscope without associated damage. The endoscope cover fixing device includes a fixing device main body and a wedge-shaped portion. Insert portions 43a, 44a into which the endoscope 31 is insertable are formed in the fixing device main body 42. The wedge-shaped portion 46 is provided in the insert holes 43a, 44a of the fixing device main body 42 to protrude to the distal end side of the fixing device main body 42. The wedge-shaped portion 46 is inlayed through a proximal end 23 side of the cover 21 into a gap between the endoscope 31 and the cover 21.