We consider the disklikeness of the planar self-affine tile
T
T
generated by an integral expanding matrix
A
A
and a consecutive collinear digit set
D
=
{
0
,
v
,
2
v
,
⋯
,
(
|
q
|
−
1
)
v
}
⊂
Z
2
{\mathcal {D}}= \{0, v, 2v, \cdots , (|q|-1)v \}\subset {\Bbb {Z}}^2
. Let
f
(
x
)
=
x
2
+
p
x
+
q
f(x)=x^{2}+ p x+ q
be the characteristic polynomial of
A
A
. We show that the tile
T
T
is disklike if and only if
2
|
p
|
≤
|
q
+
2
|
2|p|\leq |q+2|
. Moreover,
T
T
is a hexagonal tile for all the cases except when
p
=
0
p=0
, in which case
T
T
is a square tile. The proof depends on certain special devices to count the numbers of nodal points and neighbors of
T
T
and a criterion of Bandt and Wang (2001) on disklikeness.