Using the spin Hamiltonian, in which two‐spin interactions up to third neighbors and two kinds of large folded and planar cyclic four‐spin exchange terms are included, spin wave spectrum of ‘‘uudd’’ and ‘‘pseudoferromagnetic (PF)’’ phase of bcc solid 3He in finite magnetic field has been calculated. The necessary conditions for the exchange parameters to explain the first order phase transiiton from ‘‘uudd’’ to ‘‘PF’’ at magnetic field of about 0.4T and high temperature experimental results have been obtained within a framework of a three‐parameter model. By a calculation using a mean field approximation, the new phase, double spiral spin configuration has been found, and the possibility of the appearance of this phase near TN are discussed.