A sanitary cleansing apparatus comprising: a main body incorporating a water discharge nozzle that squirts water from a water discharge port; a toilet seat rotatably and pivotally supported at a relatively anterior position of the main body; and a toilet lid rotatably and pivotally supported at a relatively posterior position of the main body and generally entirely covering an upper face of the toilet seat and the main body in a closed state characterised in that the apparatus further comprises: a transmissive window provided at a rear of the toilet lid and formed from a material different from that of the toilet lid, the transmissive window including a window portion thinner than the toilet lid; and a human body detection sensor provided in the upper face of the main body and being capable of detecting a human body through the transmissive window in the closed state of the toilet lid, wherein the human body detection sensor includes a lens for focusing infrared radiation emitted from the human body and a pyroelectric element for detecting the infrared radiation, a recessed portion that is recessed relative to its surroundings is provided in the upper face of the main body, at least a portion of the lens is embedded in the recessed portion, and another portion protrudes from the main body, and the lens of the human body detection sensor is placed below the window portion of the transmissive window in the closed state of the toilet lid. a main body incorporating a water discharge nozzle that squirts water from a water discharge port; a toilet seat rotatably and pivotally supported at a relatively anterior position of the main body; and a toilet lid rotatably and pivotally supported at a relatively posterior position of the main body and generally entirely covering an upper face of the toilet seat and the main body in a closed state characterised in that the apparatus further comprises: a transmissive window provided at a rear of the toilet lid and formed from a material different from that of the toilet lid, the transmissive window including a window portion thinner than the toilet lid; and a human body detection sensor provided in the upper face of the main body and being capable of detecting a human body through the transmissive window in the closed state of the toilet lid, wherein the human body detection sensor includes a lens for focusing infrared radiation emitted from the human body and a pyroelectric element for detecting the infrared radiation, a recessed portion that is recessed relative to its surroundings is provided in the upper face of the main body, at least a portion of the lens is embedded in the recessed portion, and another portion protrudes from the main body, and the lens of the human body detection sensor is placed below the window portion of the transmissive window in the closed state of the toilet lid. a transmissive window provided at a rear of the toilet lid and formed from a material different from that of the toilet lid, the transmissive window including a window portion thinner than the toilet lid; and a human body detection sensor provided in the upper face of the main body and being capable of detecting a human body through the transmissive window in the closed state of the toilet lid, wherein the human body detection sensor includes a lens for focusing infrared radiation emitted from the human body and a pyroelectric element for detecting the infrared radiation, a recessed portion that is recessed relative to its surroundings is provided in the upper face of the main body, at least a portion of the lens is embedded in the recessed portion, and another portion protrudes from the main body, and the lens of the human body detection sensor is placed below the window portion of the transmissive window in the closed state of the toilet lid.