Abstract: We enumerate all the prime $\theta$-curves with up to seven crossings, and all the handcuff graphs with up to six crossings. We can enumerate all the prime $\theta$-curves (or handcuff graphs) in order of crossing numbers by using a prime basic $\theta$-polyhedron. A $\theta$-polyhedron is a connected planar graph embedded in 2-sphere, whose two vertices are 3-valent, and the others are 4-valent. There exist twenty-four prime basic $\theta$-polyhedra with up to seven 4-valent vertices. We can obtain a $\theta$-curve diagram (or handcuff graph diagram) from a prime basic $\theta$-polyhedron by substituting algebraic tangles for their 4-valent vertices.