PROBLEM TO BE SOLVED: To provide a portable blood volume measuring device that can be easily fit and put on a head and is stably put on without slipping off the head.SOLUTION: A portable blood volume measuring device measures blood volume in a state of being put on a head 11. The measuring device includes: a measurement part 100 for measuring the blood volume； a tabular support part for supporting the measurement part 100； and a band unit 400 having both end parts each in which the support part is disposed and a band body part 410 put on the head 11 so that the measurement part 100 is put on a temple part 13.
