PURPOSE: To make quick processing of display by compressing the data accommodated in N pieces fully in the storage area of a memory device, re- accomodating these pieces of data, entering new data one by one in the emptied storage areas, and repeating the cycle each time the memory device becomes full with data.

CONSTITUTION: As shown by block diagram for the data processing device for chromatography, a waveform memory device according to the present invention comprises an A/D converter 1 which converts a chromatographic waveform signal into digital signal at certain sampling intervals and which takes in the resultant signal, a CPU 2 which executes data taking-in, storing in memory, displaying, analytical processing, etc. while following a certain program, a ROM 3 which stores this CPU program etc. in memory, a RAM 4 having a storage area accommodating N pieces of data, a key entry part 5 for entering parameters and setting the mode, a CRT display 6 for display of the waveform, and a printer 7 for printed outputting of the analytical results etc.