A speech synthesis information editing apparatus, comprising: a phoneme storage unit that stores phoneme information that designates a duration of each phoneme of speech to be synthesized; and a feature storage unit that stores feature information that designates a time variation in a feature of the speech; characterized in that said speech synthesis information editing apparatus further comprises a display control unit that, in response to a user operation to designate a section of the speech to be edited, displays an edit screen containing a phoneme sequence image and a feature profile image on a display device in correspondence to the designated section of the speech, the phoneme sequence image being a sequence of phoneme indicators arranged along a time base in correspondence to the phonemes of the speech of the designated section, each phoneme indicator having a length set according to the duration designated by the phoneme information, the feature profile image representing a time series of points (α) representing values of the feature designated by the feature information and being arranged along the same time base; and an edition processing unit that changes a duration of each phoneme designated by the phoneme information and contained in the designated section with an expansion/compression degree depending on each value of the feature which corresponds to each phoneme and which is edited in response to a user operation performed on the edit screen, and that does not change a positional relationship of the points on the time base relative to a sounding interval of the phoneme before and after changing the duration of each phoneme, wherein the display control unit updates the edit screen based on a processing result of the edition processing unit. a phoneme storage unit that stores phoneme information that designates a duration of each phoneme of speech to be synthesized; and a feature storage unit that stores feature information that designates a time variation in a feature of the speech; characterized in that said speech synthesis information editing apparatus further comprises a display control unit that, in response to a user operation to designate a section of the speech to be edited, displays an edit screen containing a phoneme sequence image and a feature profile image on a display device in correspondence to the designated section of the speech, the phoneme sequence image being a sequence of phoneme indicators arranged along a time base in correspondence to the phonemes of the speech of the designated section, each phoneme indicator having a length set according to the duration designated by the phoneme information, the feature profile image representing a time series of points (α) representing values of the feature designated by the feature information and being arranged along the same time base; and an edition processing unit that changes a duration of each phoneme designated by the phoneme information and contained in the designated section with an expansion/compression degree depending on each value of the feature which corresponds to each phoneme and which is edited in response to a user operation performed on the edit screen, and that does not change a positional relationship of the points on the time base relative to a sounding interval of the phoneme before and after changing the duration of each phoneme, wherein the display control unit updates the edit screen based on a processing result of the edition processing unit.