A sound signal processing apparatus comprising: a sliding operation detecting section to which a sound signal collected by at least one microphone is inputted, and which determines the start and end of a sliding operation by a determination process (55, 55L, 55R) using a sliding sound signal component in the inputted sound signal, the sliding sound signal component being produced by the sliding operation on the at least one microphone itself or its vicinity; a sliding guide section that is formed in the vicinity of the at least one microphone and guides the sliding operation; and a control section that performs a predetermined control process that is set with respect to the sliding operation during a period, wherein the period is from the start to the end of the sliding operation and is determined by the sliding operation detecting section, and the sliding sound signal component is produced by the sliding operation on a material from which the at least one microphone itself or its vicinity is made and the sliding operation detecting section includes a first filter (52, 52L, 52R) configured to filter the sliding sound signal component with a filter characteristic determined in accordance with the material from which the at least one microphone or its vicinity is made to produce a first filtered signal, and a second low pass filter (54, 54L, 54R) configured to convert the first filtered signal into an envelope signal representing the energy level of the sliding sound signal component, and determination process (55, 55L, 55R) determines the start of the sliding operation at a time when the energy level of the sliding sound signal component is equal to or higher than a first level, and determined, after the start is determined, the end of the sliding operation at a time when the energy level of the sliding sound signal component is lower than a second level. a sliding operation detecting section to which a sound signal collected by at least one microphone is inputted, and which determines the start and end of a sliding operation by a determination process (55, 55L, 55R) using a sliding sound signal component in the inputted sound signal, the sliding sound signal component being produced by the sliding operation on the at least one microphone itself or its vicinity; a sliding guide section that is formed in the vicinity of the at least one microphone and guides the sliding operation; and a control section that performs a predetermined control process that is set with respect to the sliding operation during a period, wherein the period is from the start to the end of the sliding operation and is determined by the sliding operation detecting section, and the sliding sound signal component is produced by the sliding operation on a material from which the at least one microphone itself or its vicinity is made and the sliding operation detecting section includes a first filter (52, 52L, 52R) configured to filter the sliding sound signal component with a filter characteristic determined in accordance with the material from which the at least one microphone or its vicinity is made to produce a first filtered signal, and a second low pass filter (54, 54L, 54R) configured to convert the first filtered signal into an envelope signal representing the energy level of the sliding sound signal component, and determination process (55, 55L, 55R) determines the start of the sliding operation at a time when the energy level of the sliding sound signal component is equal to or higher than a first level, and determined, after the start is determined, the end of the sliding operation at a time when the energy level of the sliding sound signal component is lower than a second level.