To provide a multi-chip image sensor for which a desired performance is secured and then a chip size is reduced.

In the driving method of the photoelectric converter provided with a plurality of sensor chips 1 having a plurality of unit blocks including a plurality of light-receiving elements 2, first switches 11 for reading the signals of the respective light-receiving elements 2 and a second switch 3 provided for a plurality of first switches 11 to read signals from the first switches 11 and a common signal read line for reading the signals of the light-receiving elements 2 of the plurality of sensor chips 1, the signals of one light-receiving element 2 included in the plurality of unit blocks are read to the common signal read line successively and then the signals of the light-receiving elements 2 included in the unit block of the other sensor chip are read to the common signal read line prior to those of the light-receiving element of the same sensor chip 1 which are not read yet to the common signal read line.