An X-ray line detector includes a housing having an upper part a lower part and a linear inlet slot for X-ray radiation to be detected. At least one detector element including a plurality of linearly arranged photodiodes is disposed opposite the inlet slot. Each photodiode is arranged on a printed circuit board mounted on a base carrier disposed in the housing. Each photodiode has a multiplicity of pixels including respective active areas of equal width arranged equidistantly in relation to each other with distances between the active areas being equidistant. Adjacent printed circuit boards are spaced apart from each other at a distance such that edge pixels on the respective adjacent printed circuit boards are disposed at a distance from one another corresponding to a sum of the width of the active area of a pixel and twice the distance between adjacent pixels of a photodiode.