1. An analysis object determination device comprising a memory storing instructions; and at least one processor configured to process the instructions to: acquire a plurality of call data; acquire one or more call search criteria to narrow down call data to calls matching the search criteria; detect a plurality of specific utterance sections on the basis of data related to a voice in a conversation of the narrowed down call data, the specific utterance sections corresponding to each of a plurality of types of specific events originating from one or a plurality of participants in the conversation; exclude the narrowed down call data that does not include the specific utterances; identify, within the narrowed down call data that were not excluded, at least one reference time point including a point at which a cause of a specific event may have occurred, related to at least one specific event represented by the plurality of specific utterance sections detected; determine, on the basis of the plurality of specific utterance sections detected and within the narrowed down call data that were not excluded, one or more cause analysis sections relating to the specific event originating from the conversation participant, the number of the cause analysis sections being fewer than the number of the plurality of specific utterance sections, when determining, as the cause analysis section, a specific time range defined about the at least one reference time identified; present a user interface categorizing results of the speech analysis, the user interface permitting a user to search for particular cause analysis sections causing the particular emotion of the specific utterance section within the conversation by keyword, and permitting the user to narrow down the cause analysis sections by categories, the user interface presenting the user with specific locations in which the cause analysis sections are located in the conversation; detect a plurality of first specific utterance sections representing dissatisfaction of a first conversation participant and a second specific utterance section representing apology of a second conversation participant; determine a cause analysis section with respect to the dissatisfaction of the first conversation participant, wherein in speech analysis of the conversation, the specific utterance sections correspond to a particular emotion of the one of the participants in the conversation, and the cause analysis sections correspond to parts of the conversation causing the particular emotion, such that determination of the cause analysis sections solves a speech analysis technical problem of locating the cause analysis sections causing the particular emotion of the specific utterance sections within the conversation, wherein in identifying at least one reference time point, the reference time point is identified so as to include a head portion of the combined section, wherein the parts of the conversation causing the particular emotion are different than the specific utterance sections corresponding to the particular emotion, wherein the user interface includes a plurality of call columns within an analysis result display area within which the cause analysis sections are displayed, the identification information displayed in the user interface in chronological order of the calls, and wherein the parts of the conversation causing the particular emotion are analysis results, complaints within the calls dealt with based on the analysis results.