A parallel type analog-digital converter having a plural number (1023) of comparators, a first voltage divider comprising a plural number (1023) of resistors (R.sub.1 to R.sub.1023) connected in series across positive and negative terminals of a power source thereby feeding reference voltages from the junction points to the comparators, the apparatus further comprisesa second voltage divider comprising a second plural number (8) of resistors (r.sub.1, r.sub.2 . . . r.sub.8) connected in series across the voltage feeding terminals thereby feeding input voltages to input terminals of the current amplifiers D.sub.1, D.sub.2 . . . D.sub.8, the output of which is given to the corresponding junction points of the first voltage divider, thereby to equalize voltages of said first voltage divider with voltages of corresponding junction points of said second voltage divider.