An evaluation method for evaluating a vertical-direction height of each of a plurality of module mounting surfaces of a plurality of support arms of a mounting base, the plurality of support arms being parallel to each other, the plurality of module mounting surfaces allowing a plurality of solar cell modules to be attached thereto, the evaluation method comprising the steps of: radiating a laser beam from a laser radiation unit mounted on a reference surface of a biaxial drive part of an assembly including a horizontal shaft and the mounting base, the assembly being mounted on a pedestal by mounting the biaxial drive part on an upper surface of the pedestal; on each of the plurality of module mounting surfaces arranged in a longitudinal direction of the support arms, mounting a measurement unit in order, and by the measurement unit, receiving the laser beam radiated by the laser radiation unit, on each of the plurality of module mounting surfaces, every time the measurement unit is mounted on each of the plurality of module mounting surfaces; by the measurement unit, detecting a vertical-direction height of each of the plurality of module mounting surfaces on the basis of a reception position of the laser beam in the measurement unit, every time the measurement unit is sequentially mounted on each of the plurality of module mounting surfaces; and by a data processing device, outputting, for each of the plurality of module mounting surfaces, a height adjustment value so as to allow light receiving surfaces of the plurality of solar cell modules to form one flat surface, on the basis of respective differences between the vertical-direction heights of the plurality of module mounting surfaces detected by the measurement unit and a predetermined reference height in a vertical direction. radiating a laser beam from a laser radiation unit mounted on a reference surface of a biaxial drive part of an assembly including a horizontal shaft and the mounting base, the assembly being mounted on a pedestal by mounting the biaxial drive part on an upper surface of the pedestal; on each of the plurality of module mounting surfaces arranged in a longitudinal direction of the support arms, mounting a measurement unit in order, and by the measurement unit, receiving the laser beam radiated by the laser radiation unit, on each of the plurality of module mounting surfaces, every time the measurement unit is mounted on each of the plurality of module mounting surfaces; by the measurement unit, detecting a vertical-direction height of each of the plurality of module mounting surfaces on the basis of a reception position of the laser beam in the measurement unit, every time the measurement unit is sequentially mounted on each of the plurality of module mounting surfaces; and by a data processing device, outputting, for each of the plurality of module mounting surfaces, a height adjustment value so as to allow light receiving surfaces of the plurality of solar cell modules to form one flat surface, on the basis of respective differences between the vertical-direction heights of the plurality of module mounting surfaces detected by the measurement unit and a predetermined reference height in a vertical direction.