A biological-data processing apparatus includes a processor; and a memory that includes instructions, which when executed, cause the processor to execute performing an addition-averaging process every time an addition count of biological data reaches a predetermined count, the biological data being measured in response to a trigger signal associated with a stimulus applied to one or more parts; storing, in a storage, addition-average data resulting from the addition-averaging process performed for each of the stimulated one or more parts, in association with the addition count in the addition-average data; and performing a biological data process based on the biological data, by using the addition-average data corresponding to each of the stimulated one or more parts, the addition-average data being acquired by referring to the storage based on the addition count that is specified.