A probe holder mounting device for a biological photometric device includes: a probe holder having a plurality of probe mounting parts to which optical fiber probes are mounted a band-like mounting device body having a plurality of insertion holes into which the probe mounting parts are to be inserted to fix the probe holder in position by means of the insertion holes belts whose one ends are respectively connected to both longitudinal ends of the mounting device body and whose other ends are engaged with each other and an adjusting belt connected to the mounting device body at a position where the probe holder is fixed in position in a lateral direction of the mounting device body.
