Abstract: FM-CW radar equipment to solve a conventional problem of failure detection caused by the carrier level of amplitude modulation dispersing too largely to adjust to a constant level within a criterion range. A novel method is applied based on that a noise level greatly varies on occurrence of a failure in radio-frequency circuit. A failure can be detected by comparing the varied noise level with a noise level in normal condition. Using this method, FM-CW radar equipment can be configured with a simple structure for detecting a failure in transmission/reception circuit. The equipment provides with a noise-level extraction circuit in radio-frequency circuit, and a comparator for comparing an output of the noise-level extraction circuit with a predetermined criterion value. An alarm is output when the comparator detects the output of the noise-level extraction circuit decreases to less than the predetermined criterion value.