A reflectance-variable mirror comprising, in the following order: a first liquid crystal cell having a guest host liquid crystal layer including liquid crystals and anisotropic dyes, a first reflective polarizing film having a first reflection axis formed in one direction, a second liquid crystal cell having a retardation-variable liquid crystal layer switching between a phase difference mode, in which a vibration direction of linearly polarized light is rotated by 90 degrees, and a non-phase difference mode, a second reflective polarizing film having a second reflection axis parallel to the first reflection axis; and an absorbing plate having a light absorptivity of about 90% or more in a wavelength range of 380 nm to 780 nm, wherein the reflectance-variable mirror comprises no image display panel, wherein the reflectance-variable mirror switches between mirror mode and an antireflection mode, in which the light reflectance is 10% or less, depending on whether or not a voltage is applied, wherein the reflectance-variable mirror realizes the mirror mode when the first liquid crystal cell is in a vertically oriented state and the second liquid crystal cell is in the phase difference mode in a state of no voltage application to each of the first liquid crystal cell and the second liquid crystal cell, wherein the reflectance-variable mirror realizes the antireflection mode when the first liquid crystal cell is in a horizontally oriented state and the second liquid crystal cell is in the non-phase difference mode in a state of voltage application to each of the first liquid crystal cell and the second liquid crystal cell, wherein a content of the anisotropic dye in the guest host liquid crystal layer is 0.1 wt.% or more and 1.5 wt.% or less, wherein a reflectance difference between the mirror mode and the antireflection mode of the reflectance-variable mirror is 50% or more. a first liquid crystal cell having a guest host liquid crystal layer including liquid crystals and anisotropic dyes, a first reflective polarizing film having a first reflection axis formed in one direction, a second liquid crystal cell having a retardation-variable liquid crystal layer switching between a phase difference mode, in which a vibration direction of linearly polarized light is rotated by 90 degrees, and a non-phase difference mode, a second reflective polarizing film having a second reflection axis parallel to the first reflection axis; and an absorbing plate having a light absorptivity of about 90% or more in a wavelength range of 380 nm to 780 nm, wherein the reflectance-variable mirror comprises no image display panel, wherein the reflectance-variable mirror switches between mirror mode and an antireflection mode, in which the light reflectance is 10% or less, depending on whether or not a voltage is applied, wherein the reflectance-variable mirror realizes the mirror mode when the first liquid crystal cell is in a vertically oriented state and the second liquid crystal cell is in the phase difference mode in a state of no voltage application to each of the first liquid crystal cell and the second liquid crystal cell, wherein the reflectance-variable mirror realizes the antireflection mode when the first liquid crystal cell is in a horizontally oriented state and the second liquid crystal cell is in the non-phase difference mode in a state of voltage application to each of the first liquid crystal cell and the second liquid crystal cell, wherein a content of the anisotropic dye in the guest host liquid crystal layer is 0.1 wt.% or more and 1.5 wt.% or less, wherein a reflectance difference between the mirror mode and the antireflection mode of the reflectance-variable mirror is 50% or more.