Method for measuring the deflection of a fuel element channel for a fuel element of a boiling water reactor, in which an image of the fuel element channel is taken using a camera and is evaluated photogrammetrically, having the following method steps: a) the fuel element channel is positioned in a flooded pool, b) the camera is positioned in parallel to a vertical Z axis at a height (h) above the fuel element channel and laterally offset to the fuel element channel in such a way that b1) the optical axis thereof is orientated at an acute angle (α) to an ideal central longitudinal axis of the fuel element channel, and that b2) the image plane thereof is orientated in parallel to two front-side edges (12, 18) of the fuel element channel running in parallel to a horizontal X-axis, and that b3) both of the front-side edges (12, 18) of the fuel element channel facing towards the camera are displayed in the image, c) the image positions (PL 0, PR 0, PL N and PR N) of the corner points (12R, 12L, 18R and 18L) of the front-side edges (12, 18) which are orientated in parallel to the image plane and which face towards the camera are measured in the image taken by the camera, d) either the position of an intersecting line (S i) in the image, in which an intermediate plane, which is perpendicular to the ideal central longitudinal axis and is predetermined with regard to its axial position, cuts the side surface of the fuel element channel facing towards the camera, is calculated from the known length and width of the fuel element channel, the image positions (PL 0, PR 0, PL N and PR N) of the corner points of the front-side edges and the known image width of the camera, or the axial position of this intersecting line (S i) is calculated from the position of a predetermined intersecting line (S i) in the image, e) the intersecting line (S i) is merged into the image and the image positions (PL i, PR i+, BPL i and BPR i) of the corner points of the fuel element channel lying on this intersecting line (S i) are measured, f) the image position (M i, BM i) of the central point of a stretch which connects the corner points and runs in parallel to the front-side edges is determined from the image positions (PL i, PR i+, BPL i and BPR i), g) with the aid of the known width of the fuel element channel and of the magnification of the camera known in this intersecting line (S i), the deviation of this central point from the ideal central longitudinal axis is calculated from the measured image position (M i, BM i) thereof. a) the fuel element channel is positioned in a flooded pool, b) the camera is positioned in parallel to a vertical Z axis at a height (h) above the fuel element channel and laterally offset to the fuel element channel in such a way that b1) the optical axis thereof is orientated at an acute angle (α) to an ideal central longitudinal axis of the fuel element channel, and that b2) the image plane thereof is orientated in parallel to two front-side edges (12, 18) of the fuel element channel running in parallel to a horizontal X-axis, and that b3) both of the front-side edges (12, 18) of the fuel element channel facing towards the camera are displayed in the image, b1) the optical axis thereof is orientated at an acute angle (α) to an ideal central longitudinal axis of the fuel element channel, and that b2) the image plane thereof is orientated in parallel to two front-side edges (12, 18) of the fuel element channel running in parallel to a horizontal X-axis, and that b3) both of the front-side edges (12, 18) of the fuel element channel facing towards the camera are displayed in the image, c) the image positions (PL 0, PR 0, PL N and PR N) of the corner points (12R, 12L, 18R and 18L) of the front-side edges (12, 18) which are orientated in parallel to the image plane and which face towards the camera are measured in the image taken by the camera, d) either the position of an intersecting line (S i) in the image, in which an intermediate plane, which is perpendicular to the ideal central longitudinal axis and is predetermined with regard to its axial position, cuts the side surface of the fuel element channel facing towards the camera, is calculated from the known length and width of the fuel element channel, the image positions (PL 0, PR 0, PL N and PR N) of the corner points of the front-side edges and the known image width of the camera, or the axial position of this intersecting line (S i) is calculated from the position of a predetermined intersecting line (S i) in the image, e) the intersecting line (S i) is merged into the image and the image positions (PL i, PR i+, BPL i and BPR i) of the corner points of the fuel element channel lying on this intersecting line (S i) are measured, f) the image position (M i, BM i) of the central point of a stretch which connects the corner points and runs in parallel to the front-side edges is determined from the image positions (PL i, PR i+, BPL i and BPR i), g) with the aid of the known width of the fuel element channel and of the magnification of the camera known in this intersecting line (S i), the deviation of this central point from the ideal central longitudinal axis is calculated from the measured image position (M i, BM i) thereof.