The invention discloses ring-shaped oscillator based truly random number generation circuit and truly random number generator in the technical field of integrated circuit design. The ring-shaped oscillator based truly random number generation circuit comprises an oscillation sampling circuit, a postprocessing circuit and a control voltage generation circuit which are connected in sequence; and the sampling circuit comprises a first high-frequency ring-shaped oscillation circuit, a second high-frequency ring-shaped oscillation circuit and a low-frequency ring-shaped oscillation circuit. The ring-shaped oscillator based truly random number generator comprises a three-stage truly random number generation circuit based on a ring-shaped oscillator. The invention solves the problem that a random bit stream generates low-speed phase jitter accumulating and can quickly obtain a random bit stream with better randomness.