Objective optical system for endoscope and endoscope

An objective optical system for an endoscope comprising a plurality of lenses, that forms an intermediate image at a position conjugate to an object surface and forms the intermediate image on an imaging plane again,

• wherein Conditional expressions (1) to (3) are satisfied in a case in which a maximum effective image height on the imaging plane is denoted by HI, a focal length of the objective optical system for an endoscope is denoted by f, an effective luminous flux diameter on a lens surface closest to an object of the objective optical system for an endoscope is denoted by FD, an F-Number of the objective optical system for an endoscope is denoted by FNo, and a paraxial relay magnification of the intermediate image on the imaging plane is denoted by βR,
• 0.7<HI/|f| (1)
• FD×FNo/|f|<6 (2)
• −2<βR<−0.8 (3).