The present invention provides a sensor including a detection unit having a detection electrode and a polymer layer that is disposed on the detection electrode and includes a mold having a three-dimensional structure complementary to a steric structure of a microorganism to be detected. The sensor detects the microorganism based on a state of capturing the microorganism in the mold. The polymer layer is formed by a manufacturing method including: a polymerization step of polymerizing a monomer in the presence of the microorganism to be detected, to form the polymer layer having captured the microorganism on the detection electrode; a destruction step of partially destroying the microorganism captured in the polymer layer; and a peroxidation step of peroxidizing the polymer layer to release the microorganism from the polymer layer.