A measurement device includes: a first measurement unit (101) measuring first biological data at least k times (k≧2) to obtain any k first measurement values； a distributed-signature generation unit (104) executing signature operations for the k first measurement values using any various k distributed-signature keys, respectively, to generate k distributed signatures, where the k distributed-signature keys can reconstruct a signature generation key only when all of them are available； a signature synthesis unit (106) synthesizing the k distributed signatures together to reconstruct a signature； and a steady state verification unit (107) verifying, using a signature verification key corresponding to the signature generation key, whether or not the signature reconstructed by the signature synthesis unit is correct, where the correctness of the signature means that the k first measurement values are same values.
