To restrain image blurring and to realize miniaturization by constituting an optical equipment of a front group having positive power and a rear group having negative power and making it satisfy a specified condition.

This equipment is constituted of an objective optical system OL consisting of four lenses of three groups, an erect optical system PS consisting of prisms P1 and P2, and an ocular optical system EP consisting of three lenses of two groups in order from an object side. The optical system OL is constituted of the front group consisting of 1st to 3rd lenses L1 to L3 and having the positive power, and the rear group consisting of a 4th lens L4 being simple substance and having negative power. The rear surface (r7) of the rear group is constituted as an aspherical surface where lens thickness is thinner at a peripheral part in comparison with a spherical surface where paraxial radius of curvature is equal, that is, the lens curve is gentle as it gets away from an optical axis. The 2nd and the 3rd lenses L2 and L3 are a combined lens where they are combined each other. The 4th lens L4 is an image blur correction system which can be displaced in a direction perpendicular to an optical axis O. Then, a conditional expression 1.2<m<4.0 is satisfied. Provided that (m) is the magnification of the rear group of an objective optical system.