Disclosed are a detection/quantification kit and a detection/quantification method for detecting/quantifying an analyte rapidly at a low cost and in a simple manner. Specifically, disclosed is a kit for detecting an analyte in a sample, comprising a first conjugate and a second conjugate, wherein the first conjugate comprises a first substance comprising a stimuli-responsive polymer and a first affinity substance having affinity for the analyte and bound to the first substance, and the second conjugate comprises a second substance carrying an electrical charge and a second affinity substance having affinity for the analyte and bound to the second substance. The first and second affinity substances can bind to different sites on the analyte simultaneously.