To secure high optical performance by performing size reduction and sufficient field curvature correction.

A lens optical unit comprises at least one lens arranged at the object side of a solid-state image sensor. An imaging plane of the solid-state image sensor has a non-planar shape causing the sag amount in the optical axis direction to increase with the distance from the optical axis, and satisfies the expression (1): ρ×Sag>0, where ρ represents the Petzval curvature of an optical unit equal to the expression specified in the figure, r_k represents the curvature radius of a k-th lens surface from the object side, n_k represents the refractive index of a medium before incidence to the k-th lens surface from the object side, n'_k represents the refractive index of the medium after emission from the k-th lens surface from the object side, and Sag represents the sag amount in the optical axis direction regarding an arbitrary point other than those on the optical axis on the imaging plane, with the direction toward the image side as the positive.