PROBLEM TO BE SOLVED: To support collation of a chemical mentioned with a prescription number of an injection as a dosage unit with a chemical to be mixed by a coinjection operation support device, and further to support determination on whether coinjection operation start time is proper with respect to a chemical whose allowable time from mixing to injecting is determined.SOLUTION: A coinjection operation support device 10 includes a PLC 11 connected to an HIS 2, a display 13, and a bar code reader 14, acquires injection information of the latest prescription from the HIS 2 as the prescription number of the injection as the dosage unit is input, and collates the name of the chemical to be mixed and its used amount with the name of the chemical and its used amount input by a coinjection operator. Further, the PLC 11 includes an acquisition function for coinjection operation start time, calculates the time from mixing operation start time to injection scheduled time, and outputs end display of the mixing operation when the calculated time exceeds the allowable time.
