The present invention provides a compact stereoscopic objective optical system for an endoscope that has a wide angle of view and provides a suitable stereoscopic effect, and an endoscope equipped with the same. The stereoscopic objective optical system for an endoscope includes, in order from the object side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a rear lens group GR having a positive refractive power. The rear lens group GR has a first rear group GR1 and a second rear group GR2. The first lens group G1 and the second lens group G2 are arranged so that the optical axes coincide with each other. The optical axes of the first lens group G1, the first rear group GR1, and the second rear group GR2 are located on the same plane. The optical axis of the first lens group G1 is located between the optical axis of the first rear group GR1 and the optical axis of the second rear group GR2. Each of the first rear group GR1 and the second rear group GR2 is made up of a first subgroup, an aperture stop, and a second subgroup, and the first subgroup has a negative lens. The stereoscopic objective optical system satisfies the following conditional expression (1).0 <; -f21n / fSUB ≤ 3 (1)La présente invention concerne un système optique d'objectif stéréoscopique compact pour un endoscope qui a un grand angle de vision et fournit un effet stéréoscopique approprié, et un endoscope équipé de celui-ci. Le système optique d'objectif stéréoscopique pour un endoscope comprend, dans l'ordre depuis le côté objet, un premier groupe de lentilles G1 ayant une puissance de réfraction négative, un deuxième groupe de lentilles G2 ayant une puissance de réfraction positive et un groupe de lentilles arrière GR ayant une puissance de réfraction positive. Le groupe de lentilles arrière GR comporte un premier groupe arrière GR1 et un second groupe arrière GR2. Le premier groupe de lentilles G1 et le second groupe d