A detection device configured to detect presence or an amount of a substance to be detected using an enhanced electric field based on surface plasmon resonance, the detection device comprising: a chip holder configured to hold a detection chip including a prism having an incident surface and a film formation surface, a metal film disposed on the film formation surface, and a capturing body fixed on the metal film and configured to capture a substance to be detected; a light source configured to irradiate an irradiation spot on the metal film of the detection chip held by the chip holder with excitation light (α) through the prism; a detection unit arranged to face the metal film of the detection chip held by the chip holder, the detection unit configured to detect light (β, γ) emitted from the metal film and a region on the metal film when the light source irradiates the metal film with the excitation light; and a detection range control unit configured to control a detection range of the detection unit, wherein the detection range control unit is configured to determine a first detection range of the detection unit when the detection unit detects plasmon scattered light (β) emitted from the metal film; and determine a second detection range of the detection unit when the detection unit detects fluorescence (γ) emitted from a fluorescent substance that labels the substance to be detected captured by the capturing body; characterized in that the first detection range is different from the second detection range in a position or a size, and is controlled such that, when plasmon scattered light (β) is detected, a stray light occurrence spot generated by the excitation light (α) does not fall within the first detection range, but the irradiation spot of excitation light falls within the first detection range a chip holder configured to hold a detection chip including a prism having an incident surface and a film formation surface, a metal film disposed on the film formation surface, and a capturing body fixed on the metal film and configured to capture a substance to be detected; a light source configured to irradiate an irradiation spot on the metal film of the detection chip held by the chip holder with excitation light (α) through the prism; a detection unit arranged to face the metal film of the detection chip held by the chip holder, the detection unit configured to detect light (β, γ) emitted from the metal film and a region on the metal film when the light source irradiates the metal film with the excitation light; and a detection range control unit configured to control a detection range of the detection unit, wherein the detection range control unit is configured to determine a first detection range of the detection unit when the detection unit detects plasmon scattered light (β) emitted from the metal film; and determine a second detection range of the detection unit when the detection unit detects fluorescence (γ) emitted from a fluorescent substance that labels the substance to be detected captured by the capturing body; characterized in that the first detection range is different from the second detection range in a position or a size, and is controlled such that, when plasmon scattered light (β) is detected, a stray light occurrence spot generated by the excitation light (α) does not fall within the first detection range, but the irradiation spot of excitation light falls within the first detection range determine a first detection range of the detection unit when the detection unit detects plasmon scattered light (β) emitted from the metal film; and determine a second detection range of the detection unit when the detection unit detects fluorescence (γ) emitted from a fluorescent substance that labels the substance to be detected captured by the capturing body; characterized in that the first detection range is different from the second detection range in a position or a size, and is controlled such that, when plasmon scattered light (β) is detected, a stray light occurrence spot generated by the excitation light (α) does not fall within the first detection range, but the irradiation spot of excitation light falls within the first detection range