[Object]To provide a method for measuring a target component in an erythrocyte-containing specimen with high reliability while suppressing the influence of the Ht value of the specimen.[Solution to Problem]In the measurement method of the present invention, first, prior to measurement, a relationship between amounts of the target component and a plurality of signals corresponding thereto is provided. Then, a plurality of signals derived from the target component in the erythrocyte-containing specimen are acquired with a biosensor. With reference to the relationship, the amount of the target component in the specimen is determined based on the thus-acquired plurality of signals.