A non-magnetic concrete structure having no magnetism or a very small magnetic permeability without reinforcing steel bars arranged, a sidewall for a guideway, and a method for installing the sidewall for the guideway are provided. The reinforcing steel bars-free sidewall 11 for the guideway 10 is constructed by using a non-magnetic concrete structure constructed by using a fiber-reinforced cement-based mixed material and having no reinforcing steel bars therein. The fiber-reinforced cement-based mixed material is produced by mixing non-metallic fibers or non-magnetic metal fibers into a cement-based matrix in a mixing amount of 1 to 4% for an entire volume of the cement-based matrix. The cement-based matrix is obtained by mixing a composition with water. The above composition is composed of cement, aggregate grains having a maximum grain diameter of not more than 2.5 mm, pozzolanic reaction particles having particle diameters of not more than 15 μm and supper plasticizer. The fiber-reinforced cement-based mixed material has mechanical properties: a compressive strength of not less than 150 N/mm2 and a tensile strength of not less than 5 N/mm2.