An indoor unit for an air-conditioning apparatus, the indoor unit comprising: a body having an opening; a decorative panel attached to the body to cover the opening; and a filter disposed between the body and the decorative panel, the decorative panel having an air inlet grille formed in a rectangular shape disposed at a location that faces the opening of the body, the air inlet grille having long-side wall portions (12a1, 12a2) that face each other, a plurality of short-side wall portions, a bottom portion, and hook receiving portions (12f, 12j), the plurality of short-side wall portions being disposed perpendicularly to each of the long-side wall portions (12a1, 12a2), the bottom portion being surrounded by the long-side wall portions (12a1, 12a2) and the plurality of short-side wall portions, the hook receiving portions (12f, 12j) being located in respective grille corner portions (12e1, 12e2) each located at a corresponding one of four corners of the bottom portion, the hook receiving portions (12f, 12j) including front hook receiving portions disposed on the bottom portion along a front long-side wall portion (12a1) that is one of the long-side wall portions (12a1, 12a2) of the air inlet grille, the front hook receiving portions each having a front contact wall formed in a plate shape and a front projecting portion formed in a plate shape, the front contact wall extending upward from the bottom portion, the front projecting portion projecting from an upper end of the front contact wall toward an other one of the long-side wall portions (12a1, 12a2) and facing the bottom portion, the filter being formed in a rectangular shape and having hook portions (31, 37) in respective filter corner portions (30e1, 30e2) each located at a corresponding one of four corners of the filter, the hook portions (31, 37) being engaged with the respective hook receiving portions (12f, 12j). a body having an opening; a decorative panel attached to the body to cover the opening; and a filter disposed between the body and the decorative panel, the decorative panel having an air inlet grille formed in a rectangular shape disposed at a location that faces the opening of the body, the air inlet grille having long-side wall portions (12a1, 12a2) that face each other, a plurality of short-side wall portions, a bottom portion, and hook receiving portions (12f, 12j), the plurality of short-side wall portions being disposed perpendicularly to each of the long-side wall portions (12a1, 12a2), the bottom portion being surrounded by the long-side wall portions (12a1, 12a2) and the plurality of short-side wall portions, the hook receiving portions (12f, 12j) being located in respective grille corner portions (12e1, 12e2) each located at a corresponding one of four corners of the bottom portion, the hook receiving portions (12f, 12j) including front hook receiving portions disposed on the bottom portion along a front long-side wall portion (12a1) that is one of the long-side wall portions (12a1, 12a2) of the air inlet grille, the front hook receiving portions each having a front contact wall formed in a plate shape and a front projecting portion formed in a plate shape, the front contact wall extending upward from the bottom portion, the front projecting portion projecting from an upper end of the front contact wall toward an other one of the long-side wall portions (12a1, 12a2) and facing the bottom portion, the filter being formed in a rectangular shape and having hook portions (31, 37) in respective filter corner portions (30e1, 30e2) each located at a corresponding one of four corners of the filter, the hook portions (31, 37) being engaged with the respective hook receiving portions (12f, 12j).