A photovoltaic module installation roof renewal method for installing a photovoltaic module, by using a portable roll forming machine, on a roof of a building constructed with a roof sheet having repetitively formed crests and troughs, the method comprising the steps of: interposing a heat insulator at the troughs of the roof sheet; producing a photovoltaic module installation roof panel in a length corresponding to a length of the roof at a roof renewal site by using the portable roll forming machine and transporting the photovoltaic module installation roof panel onto the roof sheet; installing the photovoltaic module installation roof panel on the roof sheet at which the heat insulator is interposed; fastening a bracket for installing a photovoltaic module on the photovoltaic module installation roof panel; and installing the photovoltaic module on the bracket; wherein the photovoltaic module installation module roof panel includes: a panel main body having, at one end portion in a width direction, a fitting projecting bar with a concave groove on a top surface thereof along a longitudinal length and, at the other end portion in the width direction, an elastic clip to be installed over a fitting projecting bar of a neighboring photovoltaic module installation roof panel, so that the fitting projecting bar is elastically inserted into the elastic clip; and a fitting rail inserted into the concave groove, wherein the elastic clip has a bracket fitting groove to be inserted into the fitting rail of the neighboring photovoltaic module installation roof panel, wherein the bracket is fitted to the bracket fitting groove. interposing a heat insulator at the troughs of the roof sheet; producing a photovoltaic module installation roof panel in a length corresponding to a length of the roof at a roof renewal site by using the portable roll forming machine and transporting the photovoltaic module installation roof panel onto the roof sheet; installing the photovoltaic module installation roof panel on the roof sheet at which the heat insulator is interposed; fastening a bracket for installing a photovoltaic module on the photovoltaic module installation roof panel; and installing the photovoltaic module on the bracket; wherein the photovoltaic module installation module roof panel includes: a panel main body having, at one end portion in a width direction, a fitting projecting bar with a concave groove on a top surface thereof along a longitudinal length and, at the other end portion in the width direction, an elastic clip to be installed over a fitting projecting bar of a neighboring photovoltaic module installation roof panel, so that the fitting projecting bar is elastically inserted into the elastic clip; and a fitting rail inserted into the concave groove, wherein the elastic clip has a bracket fitting groove to be inserted into the fitting rail of the neighboring photovoltaic module installation roof panel, wherein the bracket is fitted to the bracket fitting groove. a panel main body having, at one end portion in a width direction, a fitting projecting bar with a concave groove on a top surface thereof along a longitudinal length and, at the other end portion in the width direction, an elastic clip to be installed over a fitting projecting bar of a neighboring photovoltaic module installation roof panel, so that the fitting projecting bar is elastically inserted into the elastic clip; and a fitting rail inserted into the concave groove, wherein the elastic clip has a bracket fitting groove to be inserted into the fitting rail of the neighboring photovoltaic module installation roof panel, wherein the bracket is fitted to the bracket fitting groove.