Bob Fosse's latest musical, his first for Broadway in eight years, is not, as the title has it, a "Big Deal." But it isn't exactly small potatoes, either.

Fosse has always been the great slummer, irresistibly drawn to the lower echelons of show business -- the dance palaces, burly shows and carnival midways -- which he then refashions into hard-edged, high-precision sleaze. He's at it again in "Big Deal," which opened last night at the Broadway Theatre. But what worked so well in such musicals as "Sweet Charity" and "Chicago" pays off only fitfully this time.

Operating not only as director and choreographer, but also as author, Fosse has produced a spangled spectacle that seems to be running on two distinct tracks. On the one hand, there's the story, inspired by what I recall as a fairly hilarious 1960 Italian film, "Big Deal on Madonna Street," in which a gang of affable con men hatched a meticulous plan to rob a pawn shop and then proceeded to louse up the operation every step of the way. On the other hand, there's what you might call the Fosse applique' -- the razzle-dazzle narrators in derby hats and white gloves, the phalanx of triple-jointed dancers and the blowsy onstage band -- which is meant to counterpoint the two-bit heist with million-dollar glitz. The twain don't seem to meet all that often, however.

Fosse has transferred the setting to his favorite locale -- Chicago during the Depression -- and turned the bumbling Italian crooks into bumbling black Americans. For the score, he has repaired to the trunk of old standards, which he tends to deploy in surprising and/or ironic context. "Life Is Just a Bowl of Cherries," delivered with a beguiling moan by Loretta Devine, stands as the plaintive theme song for the enterprise. "Everybody Loves My Baby" is taken at face value; it's sung by the likable Alan Weeks -- one of the crooks, but more than that, a proud papa -- to the little bundle of joy he's forever trundling about. (Thursday, he dutifully informs his pals he's out for the heist, because he can't get a baby sitter that night.) To a prison chain gang falls "Ain't We Got Fun," along with an understandably gritty soft-shoe. And the lulling "Me and My Shadow" becomes the slick signature tune of safecracker Dancin' Dan (Gary Chapman), flanked by his "shadows," two lithe chorus girls in best body-fitting bib and tucker.

I suspect that one of the root troubles is that Fosse's angularly disciplined sense of showmanship ultimately contradicts the spirit of the story, which wants to revel in the loose-limbed ineptitude of thieves. "Big Deal" has a mushy, sentimental core, but it's been encased in the equivalent of neon and barbed wire. The lead characters are sweethearts, appropriately garbed by Patricia Zipprodt in down-and-out Depression rags. The backup cast, however, is heartless and seems to have been dressed for "Dancin'," Fosse's sleek, sybaritic long-run smash. Which way are we going here?

There's another problem. Fosse wants to impose a cinematic fluidity on this harum-scarum saga. (At one point in their stumble toward crime, the thugs actually slide down a high wire suspended over the spectators' heads.) But in doing so, he ends up robbing himself. The musical numbers are rarely allowed to expand to their full dimensions, but dissolve instead into the next scene. Peter Larkin's mobile scenery and Jules Fisher's expert lighting make the dissolving so effortless that you don't realize at first what's being sacrificed -- one musical climax after another.

The cast, headed by the toothily engaging Cleavant Derricks, who came to the fore in "Dreamgirls," can obviously coax the blues (and reds and yellows) out of a song. And the dancers, led by Wayne Cilento and Bruce Anthony Davis, have a natural instinct to scorch the floor. But just when they all start to raise the temperature, Fosse retires them so the plot can resume its lurches -- only some of which are intentional.

For every good quip ("You free?" asks gang leader Derricks, eying Devine, who'd rather no one knew she were a maid. "Ever since Lincoln," she shoots back airily), there are unfortunately two clinkers. The film traded on the quintessential nonchalance of Italians who couldn't plot a garden, let alone a robbery. But "Big Deal" doesn't exploit its black milieu beyond the orchestrations of Ralph Burns, which neatly insinuate the sounds of R&B into chipper 1930s melodies.

Still, there are pleasures afoot: Devine warbling "Button Up Your Overcoat" to Derricks in a manner that clearly suggests she'd rather he take it off; goggle-eyed Alde Lewis Jr., in a duster that descends nearly to his ankles, tap-dancing spiffily on a table top; the virginal Desiree Coleman, injecting an unexpected wail into "Ain't She Sweet," and thereby momentarily indicating that this angel is eager to singe her wings. And Fosse can still mold a dance ensemble into the fabulous, synchronized twitching machine you might also get if a crew of exhausted taxi dancers suddenly took speed.

That may not be enough, though. In today's fierce economic climate, Broadway is incapable of sustaining anything less than the all-out musical smash. "Big Deal," while no penny-ante show, never rakes in the big chips. To call it "A Pretty Good Deal," which is probably closer to the truth, is, regrettably, to seal its fate in the marketplace.

Big Deal, written, directed and choreographed by Bob Fosse. Sets, Peter Larkin; costumes, Patricia Zipprodt; lighting, Jules Fisher; orchestrations, Ralph Burns. With Cleavant Derricks, Loretta Devine, Alan Weeks, Larry Marshall, Alde Lewis Jr., Desiree Coleman, Mel Johnson Jr., Gary Chapman, Valarie Pettiford, Barbara Yeager, Bernard L. Marsh, Wayne Cilento, Bruce Anthony Davis. At the Broadway Theatre.