[en] A simple digital data recorder consisting of an interface and a magnetic tape recorder was developed to facilitate recording in the radiation measurement. The device was successfully applied to the registration of the results of environmental radiation measurements, of γ-γ coincidence experiments and of the data obtained by a multiscaler with 16 parameters. Owing to a special recording method, this simple and inexpensive digital data recorder gives good performance such that the error rate is smaller than 10^-7 with 2000 bits per inch of recording density. The transfer rate that is related to the tape speed was 3750 bits per second in a cassette recorder and 15000 bits per second in an open reel tape recorder with the speed of 7.5 inches per second of magnetic tape. This recorder can be extensively applied to recording devices not only for the radiation measurement but also for general digitalized data. (auth.)