the cover lens 215 to deflect the optical axis of the viewing optical system by 90 degrees an objective lens 218 and a solid state image pickup device 219 the objective lens 218 and the solid state image pickup device 219 are provided in a lens barrel 217 the solid state image pickup device 219 e g a charge coupled device ccd and has a light receiving surface located at an image forming position in which an object image is formed by the objective lens 218 the ccd 219 is connected to an operating portion not shown through a signal cable 220 which extends rearward within the endoscope the front end body 201 is provided with a recessed groove 222 having a flat bottom surface located behind the cover lens 215 as shown in fig1 12 and 13 the groove 222 has a lateral width substantially identical to the width of the flat surface portion 1b of the front end body 201 and a predetermined length in the longitudinal direction of the endoscope the recessed groove 222 is defined by a vertical rear end wall 222a which is provided with an air supply passage 225 and a water supply passage 226 the air supply passage 225 and the water supply passage 226 both of which open into the recessed groove 222 are connected to an air supply pipe 223 and a.