An optical modulation-type detection device has a noise detection mode having (i) an offset canceling (hereinafter referred to as “OC”) period in which (a) the light-reception signal pathway of a pulse signal converting section is cut off so that an offset of the pulse signal converting section is suppressed and (b) the light-reception signal pathway of the pulse signal converting section is reconnected while a state in which the offset is suppressed is being maintained, at an end of the OC period, and (ii) an asynchronous reception period in which whether or not asynchronous reception occurs is detected after the first period, and an object detection mode having a synchronous reception period in which whether or not synchronous reception occurs is detected after the asynchronous reception is not detected in the noise detection mode.