A method for producing a molded article of a fiber-reinforced plastic include molding a fiber-resin mixture containing an inorganic reinforcing fiber and a thermosetting resin under heat and pressure. The elapsed time since the thermosetting resin reached a molding temperature at which a hardening reaction proceeds is measured, the loss angle δ of the thermosetting resin is measured in a dynamic viscoelasticity measurement, and the relationship between the elapsed time and the loss angle δ is evaluated to calculate the range of the elapsed time, within which the loss angle δ is 0.55 to 1.57 rad after the loss angle δ reached the maximum value, as the pressurization start range. The fiber-resin mixture is heated to the molding temperature and pressure application to the fiber-resin mixture is started within the pressurization start range, to obtain the molded article of the fiber-reinforced plastic.