A C172 pilot reported inadvertently flying into class B airspace after a near midair collision.

Attributes
ACN	1457685
Time
Date	201706
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	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	VFR
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Private
Experience	Flight Crew Last 90 Days 30 Flight Crew Total 140 Flight Crew Type 130
Events
Anomaly	Airspace Violation All Types Conflict NMAC Deviation - Procedural FAR
Miss Distance	Horizontal 200 Vertical 300

Narrative:

I had reached my cruising altitude of 7500 ft; 500 ft below the class B shelf that I was flying under. I was visually scanning for traffic when I looked down to scan the instrument panel. When I looked up again; I noticed another plane approaching very quickly from my 2 o'clock position; and from what I could tell; was starting to descend. It looked apparent that they had not seen me; so I put in full power and pitched up so that I would climb above their flight path. The other aircraft continued on their original track underneath me; and when I looked at the altimeter; I was at 8050 ft; in the class B. I immediately pitched down to regain my original cruising altitude of 7500 ft. My mind was preoccupied to the resolution of the issue when it arose; and while I was taking action; I was not thinking about how close I was approaching to the bravo airspace.

Original NASA ASRS Text

Title: A C172 Pilot reported inadvertently flying into Class B Airspace after a NMAC.

Narrative: I had reached my cruising altitude of 7500 ft; 500 ft below the class B shelf that I was flying under. I was visually scanning for traffic when I looked down to scan the instrument panel. When I looked up again; I noticed another plane approaching very quickly from my 2 o'clock position; and from what I could tell; was starting to descend. It looked apparent that they had not seen me; so I put in full power and pitched up so that I would climb above their flight path. The other aircraft continued on their original track underneath me; and when I looked at the altimeter; I was at 8050 ft; in the class B. I immediately pitched down to regain my original cruising altitude of 7500 ft. My mind was preoccupied to the resolution of the issue when it arose; and while I was taking action; I was not thinking about how close I was approaching to the bravo airspace.

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.