A probe device includes a sheet-like probe holder, a plurality of light-emitting probes and a plurality of detection probes mounted on the probe holder at a predetermined interval, a sheet holding unit holding the probe holder at a predetermined position on the biological surface, and a fixing band mounting the sheet holding unit on the living body. Each of the plurality of light-emitting probes and the detection probes includes a probe body including a light emitting unit or a detection unit, and a probe mounting part detachably mounting the probe body to the probe holder at a predetermined position.