To safely treat mammal, especially human congestive heat failure with good effect by administering a compound capable of inhibiting phosphodiesterase type IV and retarding the production of tumor necrosis factor in an amount capable of treating the congestive heart failure to the mammal.

A compound capable of inhibiting phosphodiesterase type IV and retarding the production of tumor necrosis factor, preferably of formula I [R is H or the like; R1 is H or the like; R2 is formula II or the like; a broken line is a single bond or the like; m is 0-4; R3 is H or the like; R4 is H or the like; R5 is R9 or the like; R6 is a (halo substituted) methyl or the like; R9 is H or the like], [preferably, 1-(1-cyclopentyl-3-ethyl-1H-indazol-6-yl)-4-oxo- cyclohexanecarbonitrile or the like] in an amount capable of treating congestive heart failure is administered to the mammal to treat the mammal congestive heart failure. The orally administered daily dose of the compound of formula I is generally about 0.1-1,000 mg per average adult patient.