A slurry containing YBa2Cu3O7-x particles and a fine YBa2Cu3(OH)(x) colloid solution was prepared, and a large-scale bulk YBa2Cu3O7-x superconductor (about 50 mm x 35 mm x 2 mm) was produced by plastic forming without high-pressure molding. The samples molded from the slurry were dried and then fired at 1223 K in air. X-ray diffraction data indicated that the samples had the characteristic orthorhombic YBa2Cu3O7-x structure. Measurements of electrical resistance were carried out between 300 and 50 K by the standard four-probe DC electrical measurement. The samples began superconducting at an onset temperature around 92 K, and the full-transition temperature (critical temperature) (T-c) was 88.7 +/- 1.4 K. The critical current density (J(c)) measured at 77 K was about 440 A/cm(2), the value of J(c) was improved by the heat treatment under an oxygen atmosphere, and J(c) = 1.6 x 10(3) A/cm(2) was observed. Under the magnetic field (B = 1 T), the sample held its superconductivity, and demonstrated that this method can be used to produce the magnetic shielding used in magnetic resonance imaging diagnosis.