B737 captain reported inadvertently raising the flaps instead of the gear after takeoff.

Attributes
ACN	1562400
Time
Date	201807
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	Takeoff
Flight Plan	IFR
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 245
Events
Anomaly	Deviation - Procedural Published Material / Policy Deviation - Speed All Types Flight Deck / Cabin / Aircraft Event Other / Unknown

Narrative:

On takeoff from 13R; the first officer (first officer) was flying and commanded 'gear up'. Without recognition of my actions; as I was pilot monitoring; his first takeoff of our trip; I put the flap lever from flaps 1 to flaps up. Immediately after this action; the first officer commanded LNAV as he had missed engaging it during his departure brief; and I missed it during my pre-departure cleanup of the MCP (mode control panel). As I selected LNAV for him we got an 'airspeed low' aural warning. I immediately looked at the airspeed indicator and saw 155 with a yellow box around it. I told the first officer; pilot flying our airspeed was low and to accelerate; but did not recognize my error until we reached 1000 feet AGL and I went to put the flaps up. It was then I recognized the flaps were up and the gear was down. I raised the gear; the aircraft accelerated and the rest of the flight was uneventful.

Original NASA ASRS Text

Title: B737 Captain reported inadvertently raising the flaps instead of the gear after takeoff.

Narrative: On takeoff from 13R; the F/O (First Officer) was flying and commanded 'Gear Up'. Without recognition of my actions; as I was Pilot Monitoring; his first takeoff of our trip; I put the flap lever from Flaps 1 to Flaps Up. Immediately after this action; the F/O commanded LNAV as he had missed engaging it during his departure brief; and I missed it during my pre-departure cleanup of the MCP (Mode Control Panel). As I selected LNAV for him we got an 'Airspeed Low' aural warning. I immediately looked at the airspeed indicator and saw 155 with a yellow box around it. I told the F/O; Pilot Flying our airspeed was low and to accelerate; but did not recognize my error until we reached 1000 feet AGL and I went to put the flaps up. It was then I recognized the flaps were up and the gear was down. I raised the gear; the aircraft accelerated and the rest of the flight was uneventful.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.