A specimen liquid sensor apparatus includes a specimen liquid sensor having an external terminal and a reader on which the specimen liquid sensor can be detachably attached. The reader includes a first portion, a second portion that can be displaced with respect to the first portion. A connection terminal located on an upper surface of the first portion, and an external terminal of the specimen liquid sensor and a connection terminal of the reader are in contact with each other in a closed state in which the specimen liquid sensor is located between an upper surface of the first portion and a lower surface of the second portion.