Provided is a photosensor in which a cable can be easily mounted on a circuit board. A photosensor [[1]] is provided with: a housing [[2]]; a cable [[5]]; a first circuit board [[3]]; and a second circuit board [[4]]. A through-hole [[24]] is formed in the housing [[2]]. The cable [[5]] is inserted into the through-hole [[24]]. The first circuit board [[3]] and the second circuit board [[4]] are accommodated in the housing [[2]]. The first circuit board [[3]] is provided with a first connector [[34]]. The second circuit board [[4]] has a first portion [[41]] and a second portion [[42]]. The cable [[5]] is soldered to the first portion [[41]]. The second portion [[42]] is provided with a second connector [[44]]. The second connector [[44]] is inserted into the first connector [[34]]. The second circuit board [[4]] connects the cable [[5]] and the first circuit board [[3]].