A culture flask comprising a culture chamber in a flask body comprising an even bottom wall with a growth surface on the top side, an even cover wall at a section from the bottom wall, and side walls that bridge the distance between the margins of the bottom wall and cover wall, an opening that is in adjacent regions of a side wall and the even cover wall at a distance from the bottom wall, and a hollow cylindrical flask neck that is connected to the margin of the opening and is aligned at a sharp angle to the growth surface so that the serological pipette, a scraper, a cannula or another elongated device for adding or removing material can be placed on the rear corners of the growth surface from the outside through the flask neck.