<p>For the long-term maintenance and stability assessment of underground structures, it is essential to understand the time-dependent behavior of rock, including loading-rate dependence, creep, and relaxation. This article introduces the test methods developed previously by the authors to investigate the time-dependent behavior of rock using a small number of specimens in a short period of time and presents further modified methods, and new results and findings. The alternating strain-rate test provides the stress–strain curves corresponding to two strain rates from a single specimen and helps in understanding the loading-rate dependence of rock strength. Strain rate alternation was combined with multi-stage confining pressure and in this study with unloading–reloading cycles. The accelerating-creep test helps in understanding the creep failure at low stress levels and was combined with strain-rate alternation and in this study with decelerating creep to estimate the long-term creep lifetime from the short-term tests. The principle and method of the temporally changing stress and strain test, which extends the concept of creep and relaxation tests, were explained, and new test results were obtained. Based on the results of the previously and newly proposed test methods, the close relations among these time-dependent behaviors of rock were quantitatively clarified.</p>