To improve measurement precision and preservation stability of an enzyme sensor, and to reduce dispersion on the measurement accuracy between each enzyme sensor.

In this enzyme sensor having an electrode system 3 having at least a measuring electrode and a counter electrode formed on a base material, and a reaction layer 6 fixed adhesively at least on one head side of the measuring electrode of the electrode system and including an enzyme and an electronic mediator, fine cellulose powder and/or fine crystal cellulose powder are included in the reaction layer 6.