The invention relates to a biological component-measuring device comprising a biological component-measuring device proper and a channel-carrying substrate, in which a sample including a body fluid taken by a body fluid sampler is transferred to a sensor through a sample channel by a pump and a biological component in the sample is measured by the sensor, the channel-carrying substrate including:a substrate detachably countable on the biological component-measuring device propera sample channel connectable to the body fluid sampler and the sensor for measuring a biological component in the sample including the body fluid taken by the body fluid sampler, the sample channel fixed to the substrate so as to be capable of transferring the sample to the sensor by the pump anda calibrating liquid channel connectable to a calibrating liquid tank, and connected to the sample channel at a location upstream of the pump via a first flow path changeover valve, the calibrating liquid channel fixed to the substrate so as to be capable of supplying a calibrating liquid stored in the calibrating liquid tank to the sample channel.
