An automatic rendition style determining apparatus comprising a supply section that supplies performance event information in real time in accordance with a progression of a performance, characterized in that said automatic rendition style determining apparatus further comprises: a condition setting section (Jl) that sets a rendition style determination condition including time information, said time information representing a specific time length; a time measurement section (J2, S5) that measures, on the basis of the performance event information supplied in real time by said supply section, a time length of a rest between at least two notes to be generated in succession; and a rendition style determination section (J2, S6, S8, S9, S10) that makes a comparison between the specific time length represented by said time information and the time length measured by said time measurement section and, on the basis of the comparison, determines a rendition style that is to be applied to an attack portion of a current tone to be performed in real time immediately after the rest, wherein said rendition style determination section determines the rendition style by selecting any one of a normal rendition style, slur joint rendition style and tonguing rendition style, wherein the slur joint rendition style is a rendition style where at least two successive notes are interconnected by a slur with no intervening silent state and the tonguing rendition style is a rendition style where at least two successive notes are sounded with an instantaneous break therebetween, and characterised in that if the time length of the rest measured by said time measurement section is shorter than the specific time length represented by said time information but not smaller than zero, said rendition style determination section determines that the rendition style to be applied to the attack portion of the current tone is the tonguing rendition style. a condition setting section (Jl) that sets a rendition style determination condition including time information, said time information representing a specific time length; a time measurement section (J2, S5) that measures, on the basis of the performance event information supplied in real time by said supply section, a time length of a rest between at least two notes to be generated in succession; and a rendition style determination section (J2, S6, S8, S9, S10) that makes a comparison between the specific time length represented by said time information and the time length measured by said time measurement section and, on the basis of the comparison, determines a rendition style that is to be applied to an attack portion of a current tone to be performed in real time immediately after the rest, wherein said rendition style determination section determines the rendition style by selecting any one of a normal rendition style, slur joint rendition style and tonguing rendition style, wherein the slur joint rendition style is a rendition style where at least two successive notes are interconnected by a slur with no intervening silent state and the tonguing rendition style is a rendition style where at least two successive notes are sounded with an instantaneous break therebetween, and characterised in that if the time length of the rest measured by said time measurement section is shorter than the specific time length represented by said time information but not smaller than zero, said rendition style determination section determines that the rendition style to be applied to the attack portion of the current tone is the tonguing rendition style.