A photoelectric sensor, comprising a light projecting part that emits light, a light receiving part that receives light, a housing that houses the light projecting part and the light receiving part and an indicator that displays a detection result of an object being detected, wherein the housing comprises: a first surface having a light projecting/receiving surface allowing light from the light projecting part and light to the light receiving part to pass; a second surface being parallel to the first surface and located on a side opposite to the first surface; a third surface extending in a direction orthogonal to the first surface and the second surface; and an inclined surface inclined with respect to the third surface and the second surface, characterized in that the photoelectric sensor further comprises a button serving as a setting part that receives an input operation from outside to set a threshold value, an adjustment button 20 functioning as an adjustment part that receives an input operation from outside to finely adjust the threshold value that has been set, and a sealing member attached to the housing for sealing a periphery of the indicator and the button serving as a setting part, the third surface is adjacent to the first surface, the inclined surface connects the third surface and the second surface, the button serving as a setting part and the indicator are provided on the third surface in order from the side of the inclined surface, the adjustment button functioning as an adjustment part is provided on the inclined surface, a distance between the button serving as a setting part and the adjustment button functioning as an adjustment part is larger than a distance between the button serving as a setting part and the indicator, the periphery of the indicator and the button serving as a setting part are collectively sealed by the sealing member, and the third surface and/or the inclined surface has a part of an area sealed by the sealing member between the button serving as a setting part and the adjustment button functioning as an adjustment part. a first surface having a light projecting/receiving surface allowing light from the light projecting part and light to the light receiving part to pass; a second surface being parallel to the first surface and located on a side opposite to the first surface; a third surface extending in a direction orthogonal to the first surface and the second surface; and an inclined surface inclined with respect to the third surface and the second surface, characterized in that the photoelectric sensor further comprises a button serving as a setting part that receives an input operation from outside to set a threshold value, an adjustment button 20 functioning as an adjustment part that receives an input operation from outside to finely adjust the threshold value that has been set, and a sealing member attached to the housing for sealing a periphery of the indicator and the button serving as a setting part, the third surface is adjacent to the first surface, the inclined surface connects the third surface and the second surface, the button serving as a setting part and the indicator are provided on the third surface in order from the side of the inclined surface, the adjustment button functioning as an adjustment part is provided on the inclined surface, a distance between the button serving as a setting part and the adjustment button functioning as an adjustment part is larger than a distance between the button serving as a setting part and the indicator, the periphery of the indicator and the button serving as a setting part are collectively sealed by the sealing member, and the third surface and/or the inclined surface has a part of an area sealed by the sealing member between the button serving as a setting part and the adjustment button functioning as an adjustment part.