To provide a method for accurately measuring the wall surface shape of a coke oven chamber with non-contact range finders e.g. when coke is pushed out.

Antennas 1-3 for sending and receiving electromagnetic waves are installed on a ram beam 12 of a coke pushing apparatus 22 so that the measuring direction faces the wall surface of a coke oven chamber and so that the installation distances are constant; when the pushing ram 12 is inserted into the chamber, each of range finders 6-8 measures the distance from the respective antenna to the wall surface; the amount of displacement of the antenna in the direction of distance measurement and caused by the insertion is found from the difference between two measured distance values of the same measuring point obtained by different range finders; a conversion image corrected on the variation in the direction and position of a camera 14 is formed by using a measured angle value obtained by using a laser projector 18, a reflection mirror 19, a camera 20, etc.; and the amount of displacement is corrected by the antenna positions with respect to the oven body, the position being obtained from the conversion image by an image treatment apparatus 15. Thus, the wall surface shape of a coke oven chamber is accurately measured.