Abstract: A luminous fiber described below, which does not exert a harmful effect on human bodies and is capable of emitting light for a long period of time with a high luminance, and a process for producing the luminous fiber are provided.A high luminance luminous fiber comprising a core component containing a polyolefin resin and 10-60% by weight, relative to the core component, of a luminous pigment comprising sintered fine powders represented by the formula of(M.sub.0.9995-0.998 Eu.sub.0.0005-0.002)Al.sub.2 O.sub.4.(M.sub.0.9995-0.998 Eu.sub.0.0005-0.002)O.n(Al.sub.1-b-a B.sub.b Q.sub.a).sub.2 O.sub.3,wherein M represents at least one element selected from the group consisting of Sr, Ca, Mg and Ba, Q represents at least one element selected from the group consisting of Y, lanthanoid elements, Mn and Bi, a is 0.0005-0.002, b is 0.001-0.35 and n is an integer of 1-8, and a sheath component comprising a polyolefin resin containing no luminous pigment.