A linear image sensor is constituted to include a red diode line 11, a green diode line 12 and a blue diode line 13, and the green diode line 12 positioned between the red diode line 11 and the blue diode line 13 is provided with a shift of an approximately ½ pitch in the vertical direction of a photodiode as shown. Electric charge transfer channels 21, 22 and 23 for transferring signal charges detected by the photodiodes are formed close to the red diode line 11, the green diode line 12 and the blue diode line 13 respectively, and take a winding shape extended in a main scanning direction. Signal charges read onto the electric charge transfer channels 21, 22 and 23 are transferred in the main scanning direction and are output from output ends OUT31, OUT32 and OUT33.