An object of the invention is to provide a structure analyzing device and a structure analyzing method which can analyze a state change of a structure, which is caused before the structure is destroyed, such as a state change of degradation of the structure or the like. A structure analyzing device (10) according to the present invention includes a vibration detecting means (11) which detects a vibration of a structure, and an analysis means (12) which analyzes an output signal of the vibration detecting means (11). The analysis means (12) analyzes a state change of the structure by comparing a value of at least one out of a vibration amplitude of the structure and a vibration continuation time of the structure, which is measured in a state existing when carrying out analysis, with a value of at least one out of a vibration amplitude of the water service pipe and a vibration continuation time of the water service pipe which is measured in a standard state.