Provided is a semiconductor non-volatile memory device capable of improving the accuracy of trimming by creating a written state before data is written into a non-volatile memory element. The semiconductor non-volatile memory device includes: a written data transmission circuit for transmitting written data to a non-volatile memory element; a first switch connected between the non-volatile memory element and a data output terminal; a third switch connected to an output terminal of the written data transmission circuit; and a control circuit for controlling the respective switches. When a test mode signal is input, the control circuit turns on only the first switch and the third switch so as to control the written data to be output to the data output terminal before data is written into the non-volatile memory element.