The invention relates to a guide blade segment (2) of a thermal turbomachine, in particular a gas turbine, comprising a number of profiled blades (6) which are arranged on a platform (8). A plurality of securing elements (14) for securing the guide blade segment (2) to an associated guide blade support are arranged on the side of the platform (8) which is oriented away from the blade(s). The aim of the invention is to provide a guide blade segment (2) which can be produced in a simple and economical manner avoiding casting problem areas enabling the guide blade segment to be attached in a particularly reliable and secure manner to the associated guide blade support. According to the invention, at least one section of at least one of the securing elements (14) is a separately produced component which is rigidly connected to the platform (8) or to an additional section of the securing element (14).