The invention relates to a device (10) lot curing a pipeline lining, wherein the pipeline lining comprises a resin which is curable by means of electromagnetic radiation of a specified wavelength or of a specified wavelength range, comprising a housing (11) with a first (12) and a second (14) opposite end piece and with a housing body (16) which extends between the end pieces (12, 14) and with an electrical current and cooling fluid feed line which is connected to die first end piece (12), wherein the housing body (16) has radially extending arms (26), on the outer end surfaces of which here is arranged in each case at least one light-emitting diode (28), which light-emitting diodes emit light of the specified wavelength or of the specified wavelength range and are connected to the electrical current feed line, and wherein, between the arms (26), the housing (10) has cooling fluid passage openings (32) which are coupled to the cooling fluid feed line and which extend in a longitudinal direction at least in certain sections through the housing body (16), wherein the cooling fluid passage openings (32) are delimited radially to the outside in the region of the housing body (16) by longitudinal webs (24), and wherein, between the longitudinal webs (24) and the arms (26) and/or the light-emitting diodes (28) arranged on the arms (26), there is at least one gap-like outlet opening (34), which extends in a longitudinal direction, for the cooling fluid.