An intrabody introduced device comprising: a power storage section for supplying driving power to a function executing section; a detecting section for detecting a supply voltage of the power storage section; and a timing output section for outputting a detection signal for use in detecting the supply voltage using the detecting section at given timing. The detection timing of the supply voltage can be controlled in this manner, and therefore the supply voltage can be detected at timing at which the load of function executing section is low, thereby enabling efficient voltage detection. For example, if the aforementioned timing is synchronized with the blanking period of a picked-up image, a stable voltage measurement is enabled at timing at which the intrabody introduced device applies a low load.