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 , 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 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 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 in respective filter corner portions (30e1, 30e2) each located at a corresponding one of four corners of the filter , the hook portions being engaged with the respective hook receiving portions . 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 , 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 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 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 in respective filter corner portions (30e1, 30e2) each located at a corresponding one of four corners of the filter , the hook portions being engaged with the respective hook receiving portions . <EOS>