Test age and curing method of specimen for manufacturing control of high strength concrete were investigated and following results were obtained. 1) The strength correction value of high strength concrete is small in the order of Ordinary portland cement > Moderate heat portland cement > Low heat portland cement. Moreover, it was necessary to set test age of high strength concrete using Moderate heat portland cement and Low heat portland cement on the day after the 28th. 2) In the case to use portland cement, if strength test is set within 91 days, the strength correction value doesn't reach a big negative value. 3) In the case of binder water ratio is six to seven, even if strength test is set within 91 days, the strength correction value reaches a big negative value. 4) Also in the case with 3), reasonable manufacturing control can be done by the hot water cured specimen.
