Bio-device, and quantitative measurement apparatus and method using the same

A bio-device used for measuring a target substance included in a liquid sample, comprising:

• a sample application section;
• an indicator substance holding section;
• and
• a determination section,
• wherein:
• the sample application section, the indicator substance holding section, and the determination section are located so that the liquid sample applied to the sample application section is transferred to the determination section via the indicator substance holding section,
• at least the indicator substance holding section and the determination section are included in a single member,
• the indicator substance holding section has a first substance group containing a substance specifically reacting with the target substance, wherein the first substance group is held so as to be capable of being eluted by the applied liquid sample,
• the determination section has a second substance group containing a substance specifically reacting with the target substance, the second substance group being in an immobilized state, and
• in a process in which the first substance group contained in the indicator substance holding section is eluted by the action of the liquid sample applied to the sample application section and reaches the determination section together with the liquid sample while being diffused in a moving direction of the liquid sample, a holding width A of the indicator substance holding section in the moving direction of the liquid sample before the application of the liquid sample, and a diffusion width B, which is a width of the indicator substance, relative to the holding width A, in the moving direction of the liquid sample when a trailing end of the first substance group reaches the determination section, has a ratio A:B of 1:0.25 to 1:1.