A particulate-matter detecting sensor including an insulating substrate which has a detecting face, detecting conductors formed in the insulating substrate, and a heating section formed on the insulating substrate. Each detecting conductor includes a detecting electrode part, a terminal part, and a connecting part. A portion of the detecting conductor is constituted of a noble metal conductor mainly formed of at least one noble metal selected from Pt, Au, Pd, Rh and Ir. At least a portion of the connecting part is formed of a low expansion conductor mainly formed of a low expansion coefficient metal having linear expansion coefficient lower than that of the noble metal. Both conductors are joined at an overlapping part at which the noble metal conductor and the low expansion conductor are partly overlapped with each other on an insulating layer forming the insulating substrate in a normal line direction of the insulating layer.