A method of joining dissimilar metal plates of an aluminum alloy plate and a plated steel plate by means of adhesion of an adhesive and spot welding, the method comprising: a lapping step of lapping the aluminum alloy plate and the plated steel plate via the adhesive; characterized by further comprising: a pre-heating step of clamping both of the metal plates (1, 2) that have been lapped in the lapping step between a pair of electrodes (7, 7) for spot welding and applying pressure thereto, and applying a conduction current between the pair of electrodes (7, 7); a cooling step of pressurizing, after the pre-heating step, both of the metal plates (1, 2) at a pressing force which is higher than the pressing force applied at the start of the pre-heating step in a state where conduction between the electrodes (7, 7) is stopped, and continuing this pressurization at higher pressure over a predetermined cooling time; and a welding step of pressurizing, after the cooling step, both of the metal plates (1, 2) at a pressing force which is higher than the pressing force applied at the start of the pre-heating step, and welding both of the metal plates (1, 2) by applying a current which is during this welding step higher than the conduction current value in the pre-heating step between the pair of electrodes (7, 7). a lapping step of lapping the aluminum alloy plate and the plated steel plate via the adhesive; characterized by further comprising: a pre-heating step of clamping both of the metal plates (1, 2) that have been lapped in the lapping step between a pair of electrodes (7, 7) for spot welding and applying pressure thereto, and applying a conduction current between the pair of electrodes (7, 7); a cooling step of pressurizing, after the pre-heating step, both of the metal plates (1, 2) at a pressing force which is higher than the pressing force applied at the start of the pre-heating step in a state where conduction between the electrodes (7, 7) is stopped, and continuing this pressurization at higher pressure over a predetermined cooling time; and a welding step of pressurizing, after the cooling step, both of the metal plates (1, 2) at a pressing force which is higher than the pressing force applied at the start of the pre-heating step, and welding both of the metal plates (1, 2) by applying a current which is during this welding step higher than the conduction current value in the pre-heating step between the pair of electrodes (7, 7). a pre-heating step of clamping both of the metal plates (1, 2) that have been lapped in the lapping step between a pair of electrodes (7, 7) for spot welding and applying pressure thereto, and applying a conduction current between the pair of electrodes (7, 7); a cooling step of pressurizing, after the pre-heating step, both of the metal plates (1, 2) at a pressing force which is higher than the pressing force applied at the start of the pre-heating step in a state where conduction between the electrodes (7, 7) is stopped, and continuing this pressurization at higher pressure over a predetermined cooling time; and a welding step of pressurizing, after the cooling step, both of the metal plates (1, 2) at a pressing force which is higher than the pressing force applied at the start of the pre-heating step, and welding both of the metal plates (1, 2) by applying a current which is during this welding step higher than the conduction current value in the pre-heating step between the pair of electrodes (7, 7).