A washing machine comprising: a cabinet including an upper flange bent from an upper end portion of the cabinet; a pin member disposed on an upper side of the cabinet; a top cover coupled to the upper side of the cabinet; and a through hole disposed in the top cover and through which the pin member passes, wherein the pin member includes: a coupling portion coupled to the cabinet; and the upper flange includes a coupling hole into which the coupling portion is inserted, whereby the pin member includes a separation prevention portion to prevent the top cover from becoming separated from the cabinet, and whereby the washing machine is characterized in that the separation prevention portion is configured to extend obliquely upward from the coupling portion to restrict movement of the top cover to prevent the top cover from becoming separated from the cabinet; the pin member includes a guide portion extending from an upper end of the separation prevention portion in an upward direction of the cabinet so that the through hole is guided to be moved along the pin member, and an inclination angle of the separation prevention portion with respect to the upper flange is 25° to 35°. a cabinet including an upper flange bent from an upper end portion of the cabinet; a pin member disposed on an upper side of the cabinet; a top cover coupled to the upper side of the cabinet; and a through hole disposed in the top cover and through which the pin member passes, wherein the pin member includes: a coupling portion coupled to the cabinet; and the upper flange includes a coupling hole into which the coupling portion is inserted, whereby the pin member includes a separation prevention portion to prevent the top cover from becoming separated from the cabinet, and whereby the washing machine is characterized in that the separation prevention portion is configured to extend obliquely upward from the coupling portion to restrict movement of the top cover to prevent the top cover from becoming separated from the cabinet; the pin member includes a guide portion extending from an upper end of the separation prevention portion in an upward direction of the cabinet so that the through hole is guided to be moved along the pin member, and an inclination angle of the separation prevention portion with respect to the upper flange is 25° to 35°. a coupling portion coupled to the cabinet; and the upper flange includes a coupling hole into which the coupling portion is inserted, whereby the pin member includes a separation prevention portion to prevent the top cover from becoming separated from the cabinet, and whereby the washing machine is characterized in that the separation prevention portion is configured to extend obliquely upward from the coupling portion to restrict movement of the top cover to prevent the top cover from becoming separated from the cabinet; the pin member includes a guide portion extending from an upper end of the separation prevention portion in an upward direction of the cabinet so that the through hole is guided to be moved along the pin member, and an inclination angle of the separation prevention portion with respect to the upper flange is 25° to 35°.