It is well known [4, 5, 8] that a smooth minimal surface Σ spanning a rectifiable Jordan curve C satisfies the isoperimetric inequality 4πArea(Σ) ≤ Length(C) 2 , (1) where equality holds if and only if C is a circle and Σ is a disk. Some smooth minimal surfaces in R 3 can be physically realized as soap films. However, the soap films formed by dipping some wire frames in soap solution contain interior singular curves. Here arises the main question of this paper: Does (1) still hold for this soap-film-like surface with singularities? In 1986 one of Almgren's results [2] answered this question affirmatively for area minimizing flat chains mod k. In this paper we extend his two-dimensional result and show that (1) holds also for two-dimensional stationary varifolds with connected boundary of multiplicity ≥ 1 (Theorem 2). Moreover, if the bounding curve C consists of k curves having the same end points, we obtain a new type of sharp isoperimetric inequality for area minimizing flat chains mod k spanned by C. Here, unlike (1), equality holds only for the union of k flat half disks with a common diameter (Theorem 3).