A cooking appliance comprising: a housing having a bottom part , two side parts , and a back part , and a cooking compartment formed therein, wherein the housing has an upper surface and a front surface which are open; a door for opening and closing the upper surface and the front surface of the housing , wherein the door is rotatable about a rotation axis parallel to an upper edge of the back part of the housing , and wherein the door includes a door upper surface part for covering the upper surface of the housing and a door front surface part extending from a front portion of the door upper surface part for covering the front surface of the housing ; a tray disposed in the cooking compartment ; and a hinge assembly , wherein the hinge assembly includes: a mounting protrusion for removably mounting the tray thereon, wherein the mounting protrusion is movable in a horizontal or front-rear direction of the housing for inserting and withdrawing the tray in said direction, and a converting and outputting part configured to convert a rotation of the door to a linear motion of the mounting protrusion in the front-rear direction of the housing , characterized in that the hinge assembly includes: a hinge part hinge-coupled to the rear side of the door upper surface part , and whose posture is changed by interlocking with rotation of the door . a housing having a bottom part , two side parts , and a back part , and a cooking compartment formed therein, wherein the housing has an upper surface and a front surface which are open; a door for opening and closing the upper surface and the front surface of the housing , wherein the door is rotatable about a rotation axis parallel to an upper edge of the back part of the housing , and wherein the door includes a door upper surface part for covering the upper surface of the housing and a door front surface part extending from a front portion of the door upper surface part for covering the front surface of the housing ; a tray disposed in the cooking compartment ; and a hinge assembly , wherein the hinge assembly includes: a mounting protrusion for removably mounting the tray thereon, wherein the mounting protrusion is movable in a horizontal or front-rear direction of the housing for inserting and withdrawing the tray in said direction, and a converting and outputting part configured to convert a rotation of the door to a linear motion of the mounting protrusion in the front-rear direction of the housing , characterized in that the hinge assembly includes: a hinge part hinge-coupled to the rear side of the door upper surface part , and whose posture is changed by interlocking with rotation of the door . a mounting protrusion for removably mounting the tray thereon, wherein the mounting protrusion is movable in a horizontal or front-rear direction of the housing for inserting and withdrawing the tray in said direction, and a converting and outputting part configured to convert a rotation of the door to a linear motion of the mounting protrusion in the front-rear direction of the housing , characterized in that the hinge assembly includes: a hinge part hinge-coupled to the rear side of the door upper surface part , and whose posture is changed by interlocking with rotation of the door . <EOS>