the vertical registers 156 in the image section 151 need not be maintained at a constant level over the whole period of the line shift transfer 161 and it is sufficient that the line shift transfer 161 be maintained at constant level during a predetermined period prior to the smear discharge and transfer 162 as shown in fig2 at a timing t 21 immediately before the line shift transfer 161 is ended smear electric charges 171 produced in the vertical register 156 in the image section 151 are constantly discharged to the second smear drain section 157 by holding all of the vertical clocks of the image section 151 at the same constant voltage this processing is carried out during the line shift transfer 161 a smear discharge and transfer 162 is carried out after the line shift transfer 161 at a timing point t 22 the line shift transfer is ended and the potential levels of both the vertical transfer sections are made flat prior to the smear discharge and transfer 162 smear electric charges generated during the smear discharge and transfer period 162 are all sequentially discharged to the first smear drain side a timing point t 23 in fig2 shows such condition the transferred states after the timing point t 23 are similar to those provided after the timing point t 13 in the preceding embodiment and therefore need not be described in detail according to this embodiment since the smear electric charge coarse discharge period is sufficiently.